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Breaking the code: Multi-stage ‘code of conduct’ phishing campaign leads to AiTM token compromise

Phishing campaigns continue to improve sophistication and refinement in blending social engineering, delivery and hosting infrastructure, and authentication abuse to remain effective against evolving security controls. A large-scale credential theft campaign observed by Microsoft Defender Research exemplifies this trend, using code of conduct-themed lures, a multi-step attack chain, and legitimate email services to distribute fully authenticated messages from attacker-controlled domains.

The campaign targeted tens of thousands of users, primarily in the United States, and directed them through several stages of CAPTCHA and intermediate staging pages designed to reinforce legitimacy while filtering out automated defenses. The lures in this campaign used polished, enterprise-style HTML templates with structured layouts and preemptive authenticity statements, making them appear more credible than typical phishing emails and increasing their plausibility as legitimate internal communications. Because the messages contained concerning accusations and repeated time-bound action prompts, the campaign created a sense of urgency and pressure to act.  

Email threat landscape

Q1 2026 trends and insights ›

The attack chain ultimately led to a legitimate sign-in experience that was part of an adversary‑in‑the‑middle (AiTM) phishing flow, which allowed the attackers to proxy the authentication session and capture authentication tokens that could provide immediate account access. Unlike traditional credential harvesting, AiTM attacks intercept authentication traffic in real time, bypassing non-phishing-resistant multifactor authentication (MFA).

In this blog, we’re sharing our analysis of this campaign’s lures, infrastructure, and techniques. Organizations can defend against financial fraud initiated through phishing emails by educating users about phishing lures, investing in advanced anti-phishing solutions like Microsoft Defender for Office 365 and configuring essential email security settings, and encouraging users to employ web browsers that support SmartScreen. Organizations can also enable network protection, which lets Windows use SmartScreen as a host-based web proxy.

Multi-step social engineering campaign leading to credential theft

Between April 14 and 16, 2026, the Microsoft Defender Research team observed a series of sophisticated phishing campaigns targeting more than 35,000 users across over 13,000 organizations in 26 countries, with majority of targets located in the United States (92%). The campaign did not focus on a single vertical but instead impacted a broad range of industries, most notably Healthcare & life sciences (19%), Financial services (18%), Professional services (11%), and Technology & software (11%). Messages were distributed in multiple distinct waves between 06:51 UTC on April 14 and 03:54 UTC on April 16. 

Bar graph showing volume of messages sent by hour between April 14 and 16, 2026
Figure 1. Timeline of campaign messages sent by hour
Pie charts showing the breakdown of campaign recipients by country and industry.
Figure 2. Campaign recipients by country and industry

Emails in this campaign posed as internal compliance or regulatory communications, using display names such as “Internal Regulatory COC”, “Workforce Communications”, and “Team Conduct Report”. Subject lines included “Internal case log issued under conduct policy” and “Reminder: employer opened a non-compliance case log”.

Message bodies claimed that a “code of conduct review” had been initiated, referenced organization-specific names embedded within the text, and instructed recipients to “open the personalized attachment” to review case materials. At the top of each message, a notice stated that the message had been “issued through an authorized internal channel” and that links and attachments had been “reviewed and approved for secure access”, reinforcing the email’s purported legitimacy. To further support the confidentiality of the supposed review, the end of each message contained a green banner stating that the contents had been encrypted using Paubox, a legitimate service associated with HIPAA-compliant communications.

Screenshot of sample phishing email
Figure 3. Sample phishing email

Analysis of the sending infrastructure indicated that the campaign emails were sent using a legitime email delivery service, likely originating from a cloud-hosted Windows virtual machine. The messages were sent from multiple sender addresses using domains that are likely attacker-controlled.

Each campaign email included a PDF attachment with filenames such as Awareness Case Log File – Tuesday 14th, April 2026.pdf and Disciplinary Action – Employee Device Handling Case.pdf. The attachment provided additional context about the supposed conduct review, including a summary of the review process and instructions for accessing supporting documentation. Recipients were directed to click a “Review Case Materials” link within the PDF, which initiated the credential harvesting flow.

Screenshot of PDF attachment used in the campaign
Figure 4. PDF attachment

When clicked, users were initially directed to one of two attacker-controlled domains (for example, acceptable-use-policy-calendly[.]de or compliance-protectionoutlook[.]de). These landing pages displayed a Cloudflare CAPTCHA, presented as a mechanism to validate that the user was coming “from a valid session”. This CAPTCHA likely served as a gating mechanism to impede automated analysis and sandbox detonation. 

Screenshot of captcha challenge.
Figure 5. CAPTCHA challenge

After completing the CAPTCHA, users were redirected to an intermediate site designed to prepare them for the final stage of the attack. This page informed users that the requested documentation was encrypted and required account authentication. While this stage of the attack has several hallmarks of device code phishing, we were only able to confirm the AITM portion of the attack chain.

Screenshot of intermediate site asking users to click review & sign button
Figure 6. Intermediate site asking users to click “Review & Sign”

After clicking the provided “Review & Sign” button, users were presented with a sign-in prompt requesting their email address.

Screenshot of prompt directing users to enter email address
Figure 7. Prompt directing users to enter their email address

After submission, users were required to complete a second CAPTCHA involving image selection.

Screenshot of second captcha challenge
Figure 8. Second CAPTCHA challenge

Once these steps were completed, users were shown a message indicating that verification was successful and that their “case” was being prepared.

Screenshot of message telling users that verification completed successfully
Figure 9. Message telling users that “Verification completed successfully”

Following these steps, users were redirected to a third site hosting the final stage of the attack. Analysis of the underlying code indicates that the final destination varied depending on whether the user accessed the workflow from a mobile device or a desktop system.

Screenshot of code used to redirect users based on platform, whether mobile or dekstop
Figure 10. Code used to redirect users based on platform

On the final page, users were informed that all materials related to their code of conduct review had been “securely logged”, “time-stamped”, and “maintained within the organization’s centralized compliance tracking system”. They were then prompted to schedule a time to discuss the case, which required signing in to their account.

screenshot of final page instructing users to sign in
Figure 11. Final page instructed users to sign in

Selecting the “Sign in with Microsoft” option redirected users to a Microsoft authentication page, initiating an AiTM session hijacking flow designed to capture authentication tokens and compromise user accounts.

Mitigation and protection guidance

Microsoft recommends the following mitigations to reduce the impact of this threat. Check the recommendations card for the deployment status of monitored mitigations.

  • Review the recommended settings for Exchange Online Protection and Microsoft Defender for Office 365 to ensure your organization has established essential defenses and knows how to monitor and respond to threat activity.
  • Invest in user awareness training and phishing simulations. Attack simulation training in Microsoft Defender for Office 365, which also includes simulating phishing messages in Microsoft Teams, is one approach to running realistic attack scenarios in your organization.
  • Enable Zero-hour auto purge (ZAP) in Defender for Office 365 to quarantine sent mail in response to newly acquired threat intelligence and retroactively neutralize malicious phishing, spam, or malware messages that have already been delivered to mailboxes.
  • Responders could also manually check for and purge unwanted emails containing URLs and/or Subject fields that are similar, but not identical, to those of known bad messages. Investigate malicious email that was delivered in Microsoft 365 and use Threat Explorer to find and delete phishing emails.
  • Turn on Safe Links and Safe Attachments in Microsoft Defender for Office 365.
  • Enable network protection in Microsoft Defender for Endpoint.
  • Encourage users to use Microsoft Edge and other web browsers that support Microsoft Defender SmartScreen, which identifies and blocks malicious websites, including phishing sites, scam sites, and sites that host malware.
  • Enable password-less authentication methods (for example, Windows Hello, FIDO keys, or Microsoft Authenticator) for accounts that support password-less. For accounts that still require passwords, use authenticator apps like Microsoft Authenticator for multifactor authentication (MFA). Refer to this article for the different authentication methods and features.
  • Configure automatic attack disruption in Microsoft Defender XDR. Automatic attack disruption is designed to contain attacks in progress, limit the impact on an organization’s assets, and provide more time for security teams to remediate the attack fully.

Microsoft Defender detections

Microsoft Defender customers can refer to the list of applicable detections below. Microsoft Defender coordinates detection, prevention, investigation, and response across endpoints, identities, email, apps to provide integrated protection against attacks like the threat discussed in this blog.

Tactic Observed activity Microsoft Defender coverage 
Initial accessPhishing emailsMicrosoft Defender for Office 365
– A potentially malicious URL click was detected
– A user clicked through to a potentially malicious URL
– Suspicious email sending patterns detected
– Email messages containing malicious URL removed after delivery
– Email messages removed after delivery
– Email reported by user as malware or phish
PersistenceThreat actors sign in with stolen valid entitiesMicrosoft Entra ID Protection
– Anomalous Token
– Unfamiliar sign-in properties
– Unfamiliar sign-in properties for session cookies  

Microsoft Defender for Cloud Apps
– Impossible travel activity

Microsoft Security Copilot

Microsoft Security Copilot is embedded in Microsoft Defender and provides security teams with AI-powered capabilities to summarize incidents, analyze files and scripts, summarize identities, use guided responses, and generate device summaries, hunting queries, and incident reports.

Customers can also deploy AI agents, including the following Microsoft Security Copilot agents, to perform security tasks efficiently:

Security Copilot is also available as a standalone experience where customers can perform specific security-related tasks, such as incident investigation, user analysis, and vulnerability impact assessment. In addition, Security Copilot offers developer scenarios that allow customers to build, test, publish, and integrate AI agents and plugins to meet unique security needs.

Threat intelligence reports

Microsoft Defender XDR customers can use the following threat analytics reports in the Defender portal (requires license for at least one Defender XDR product) to get the most up-to-date information about the threat actor, malicious activity, and techniques discussed in this blog. These reports provide the intelligence, protection information, and recommended actions to prevent, mitigate, or respond to associated threats found in customer environments.

Microsoft Security Copilot customers can also use the Microsoft Security Copilot integration in Microsoft Defender Threat Intelligence, either in the Security Copilot standalone portal or in the embedded experience in the Microsoft Defender portal to get more information about this threat actor.

Hunting queries

Microsoft Defender XDR customers can run the following advanced hunting queries to find related activity in their networks:

Campaign emails by sender address

The following query identifies emails associated with this campaign using a message’s sending email address.

EmailEvents
| where SenderMailFromAddress in (" cocpostmaster@cocinternal.com "," nationaladmin@gadellinet.com ","
nationalintegrity@harteprn.com”,” m365premiumcommunications@cocinternal.com”,” documentviewer@na.businesshellosign.de”)

Indicators of compromise

IndicatorTypeDescriptionFirst seenLast seen
compliance-protectionoutlook[.]deDomainDomain hosting malicious campaign content2026-04-142026-04-16
acceptable-use-policy-calendly[.]deDomainDomain hosting malicious campaign content2026-04-142026-04-16
cocinternal[.]comDomainDomain hosting sender email address2026-04-142026-04-16
Gadellinet[.]comDomainDomain hosting sender email address2026-04-142026-04-16
Harteprn[.]comDomainDomain hosting sender email address2026-04-142026-04-16
Cocpostmaster[@]cocinternal.comEmail addressEmail address used to send campaign emails2026-04-142026-04-16
Nationaladmin[@]gadellinet.comEmail addressEmail address used to send campaign emails2026-04-142026-04-16
Nationalintegrity[@]harteprn.comEmail addressEmail address used to send campaign emails2026-04-142026-04-16
M365premiumcommunications[@]cocinternal.comEmail addressEmail address used to send campaign emails2026-04-142026-04-16
Documentviewer[@]na.businesshellosign.deEmail addressEmail address used to send campaign emails2026-04-142026-04-16
Awareness Case Log File – Monday 13th, April 2026.pdfFilenameName of PDF attachment containing phishing link2026-04-142026-04-14
Awareness Case Log File – Tuesday 14th, April 2026.pdfFilenameName of PDF attachment containing phishing link2026-04-152026-04-15
Awareness Case Log File – Wednesday 15th, April 2026.pdfFilenameName of PDF attachment containing phishing link2026-04-162026-04-16
5DB1ECBBB2C90C51D81BDA138D4300B90EA5EB2885CCE1BD921D692214AECBC6SHA-256File hash of campaign PDF attachment2026-04-14  2026-04-16  
B5A3346082AC566B4494E6175F1CD9873B64ABE6C902DB49BD4E8088876C9EADSHA-256File hash of campaign PDF attachment2026-04-142026-04-16
11420D6D693BF8B19195E6B98FEDD03B9BCBC770B6988BC64CB788BFABE1A49DSHA-256File hash of campaign PDF attachment2026-04-142026-04-16

Learn more

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The post Breaking the code: Multi-stage ‘code of conduct’ phishing campaign leads to AiTM token compromise appeared first on Microsoft Security Blog.

Email threat landscape: Q1 2026 trends and insights

During the first quarter of 2026 (January-March), Microsoft Threat Intelligence detected approximately 8.3 billion email-based phishing threats, with monthly volumes declining slightly from 2.9 billion in January to 2.6 billion in March. By the end of the quarter, QR code phishing emerged as the fastest-growing attack vector, more than doubling over the period, while CAPTCHA-gated phishing evolved rapidly across payload types. Overall, 78% of email threats were link-based, while malicious payloads accounted for 19% of attacks in January—boosted by large HTML and ZIP campaigns—before settling at 13% in both February and March. Credential phishing remained the dominant objective behind malicious payloads throughout the quarter. This shift toward link-based delivery, combined with the payload trends, suggests that threat actors increasingly preferred hosted credential phishing infrastructure over locally-rendered payloads as the quarter progressed.

These trends reflect how threat actors continue to iterate on both scale and delivery techniques to improve effectiveness. At the same time, disruption efforts can meaningfully impact this activity. Following Microsoft’s Digital Crime Unit-led action against the Tycoon2FA phishing-as-a-service (PhaaS) platform in early March, associated email volume declined 15% over the remainder of the month, alongside a significant reduction in access to active phishing pages, limiting the platform’s immediate effectiveness. While Tycoon2FA has since adapted by shifting hosting providers and domain registration patterns, these changes reflect partial recovery rather than full restoration of previous capabilities. Alongside these shifts, business email compromise (BEC) activity remained prevalent, totaling approximately 10.7 million attacks in the quarter, largely driven by low-effort, generic outreach messages. At the same time, Microsoft Defender Research observed early indications of emerging techniques such as device code phishing—sometimes enabled by offerings like EvilTokens—which, while not yet at the scale of the trends discussed below, reflect continued innovation in credential theft methods.

This blog provides a view of email threat activity across the first quarter of 2026, highlighting key trends in phishing techniques, payload delivery, and threat actor behavior observed by Microsoft Threat Intelligence. We examine shifts in QR code phishing, CAPTCHA evasion tactics, malicious payloads, and BEC activity, analyze how disruption efforts and infrastructure changes influenced threat actor operations, and provide recommendations and Microsoft Defender detections to help mitigate these threats. By bringing these trends together, this blog can help defenders understand how email-based attacks are evolving and where to focus detection, mitigation, and user protection strategies.

Tycoon2FA disruption impact

Since its emergence in August 2023, Tycoon2FA has rapidly become one of the most widespread PhaaS platforms, leveraging adversary-in-the-middle (AiTM) techniques to attempt to defeat non-phishing-resistant multifactor authentication (MFA) defenses. The group behind the PhaaS platform (tracked by Microsoft Threat Intelligence as Storm-1747) leases malicious infrastructure and sells phishing kits that impersonate various enterprise application sign-in pages and incorporate evasion tactics, such as fake CAPTCHA pages.

The quarter began with Tycoon2FA in a period of reduced activity. January volumes represented a 54% decline from December 2025, marking the second consecutive month of sharp decreases. While post-holiday seasonal effects may have contributed to this decrease in volume, some of the reduction might also have been the result of Microsoft’s Digital Crimes Unit disruption of RedVDS, a service used by many Tycoon2FA customers to distribute malicious email campaigns.

After surging 44% in February, phishing attacks pointing to Tycoon2FA fell 15% in March driven largely by the effects of a coordinated disruption operation. In early March 2026, Microsoft’s Digital Crimes Unit, in coordination with Europol and industry partners, took action to disrupt Tycoon2FA’s infrastructure and operations, significantly impairing the platform’s hosting capabilities. While Tycoon2FA-linked messages continued to circulate after the disruption, almost one-third of March’s total volume was concentrated in a three-day period early in the month; daily volumes for the remainder of March were notably lower than historical averages, and targets’ ability to reach active phishing pages was substantially reduced.

Line graph displays monthly phishing email volume from November to March for Tycoon2FA, showing a sharp decline from about 23 million in November to around 9 million in January, followed by a slight increase and stabilization near 11 million in February and March.
Figure 1. Tycoon2FA monthly malicious messages volume (November 2025 – March 2026)

Tycoon2FA’s infrastructure composition evolved multiple times during the first three months of 2026. In January, Tycoon2FA domains started shifting toward newer generic top-level domains (TLDs) such as .DIGITAL, .BUSINESS, .CONTRACTORS, .CEO, and .COMPANY, moving away from previous commonly used TLDs or second-level domains like .SA.COM, .RU, and .ES. This trend became even more well-established in February. Following the March disruption, however, Microsoft Threat Intelligence observed a notable increase in Tycoon2FA domains with .RU registrations, with more than 41% of all Tycoon2FA domains using a .RU TLD since the last week of March.

Line chart showing percentage trends of Tycoon2FA TLDs and 2LDs from November 2025 to March 2026, with six categories: SA.COM, RU, ES, DIGITAL, DE, and DEV. SA.COM starts highest near 22% and declines to about 6%, while RU rises sharply from 13% to 23% in March, with other categories remaining below 7% throughout.
Figure 2. Top TLDs and second-level domains (2LDs) associated with Tycoon2FA infrastructure (November 2025 – March 2026)

Additionally, toward the end of March, we saw Tycoon2FA moving away from Cloudflare as a hosting service and now hosts most of its domains across a variety of alternative platforms, suggesting the group is attempting to find replacement services that offer comparable anti-analysis protections.  

QR code phishing attacks

In recent years, QR codes have rapidly emerged as a preferred tool among phishing threat actors seeking to bypass traditional email defenses. By embedding malicious URLs within image-based QR codes in the body of an email or within the contents of an attachment, threat actors attempt to exploit the limitations of text-based scanning engines and redirect victims to phishing sites on unmanaged mobile devices.

The most significant shift in Q1 2026 was the rapid escalation of QR code phishing, with attack volumes increasing from 7.6 million in January to 18.7 million in March, a 146% increase over the quarter. After an initial 35% decline in January (continuing a late-2025 downtrend), volumes reversed course dramatically, growing 59% in February and another 55% in March. By the end of the quarter, QR code phishing had reached its highest monthly volume in at least a year.

Line graph showing weekly volume of QR-code phishing attacks from November 2025 to March 2026, with phishing email counts fluctuating and peaking in March 2026.
Figure 3. Trend of QR code phishing attacks by weekly volume (November 2025 – March 2026)

PDF attachments were the dominant delivery method throughout the quarter, growing from 65% of QR code attacks in January to 70% in March. While the overall volume of DOC/DOCX payloads containing malicious QR codes steadily increased each month, their share of overall delivery payloads decreased from 31% in January to 24% in March. A notable late-quarter development was the emergence of QR codes embedded directly in email bodies, which surged 336% in March. While still a small share of total volume (5%), this approach eliminates the need for an attachment altogether and highlights a shift in threat actor delivery methods that defenders should continue to monitor.

CAPTCHA tactics

Threat actors use CAPTCHA pages to delay detection and increase user interaction. These pages function as a visual decoy, giving the appearance of a legitimate security check while concealing a transition to malicious content. By forcing users to engage with the CAPTCHA before accessing the payload, threat actors reduce the likelihood of automated scanning tools identifying the threat and increase the chances of successful credential harvesting or malware delivery. Additionally, fake CAPTCHAs are used in ClickFix attacks to trick users into copying and executing malicious commands under the guise of human verification, allowing malware to bypass conventional security controls.

After declining in both January (-45%) and February (-8%), CAPTCHA-gated phishing volumes exploded in March, more than doubling (+125%) to 11.9 million attacks, the highest volume observed over the last year.

Line chart showing CAPTCHA-gated phishing volume between November 2025 and March 2026. The chart highlights a peak around December, a decline through January and February, followed by a sharp increase in March to over 12 million attacks.
Figure 4. CAPTCHA-gated phishing volume (November 2025 – March 2026)

The most notable aspect of Q1 CAPTCHA trends was the rapid rotation of delivery methods, as threat actors appeared to actively experiment with which payload formats most effectively evade email defenses:

  • HTML attachments started the year as the most common method to deliver CAPTCHA-gated phishing (37% in January), but dropped 34% in February, hitting its lowest monthly volume since August 2025. Although their volume more than doubled in March, hitting an annual monthly high, HTML files were still only the second-most common delivery method to close the quarter.
  • SVG files, which had seen consecutive months of decreasing volumes, grew by 49% in February at the same time nearly every other delivery payload type decreased. Because of this, it was the most common delivery method for the month, which had not happened since November 2025. This one-month spike reversed itself in March, however, and the number of SVG files delivering CAPTCHA-gated phish fell by 57%, accounting for just 7% of delivery payloads.
  • PDF files saw a meteoric rise in volume during the first quarter of the year. After seeing steady month-over-month declines since July 2025, and hitting an annual monthly low point in January 2026, the number of PDF attachments leading to CAPTCHA-gated phishing sites more than quadrupled in March (+356%). Not only did it retake its spot as the most common delivery method for these attacks since last July, but it eclipsed its annual high by more than 37%.
  • DOC/DOCX files, which didn’t make up more than 9% of CAPTCHA-gated phishing payloads over the previous nine months, increased almost five times (+373%) in March to account for 15% of payloads.
  • Email-embedded URLs, which had once delivered more than half of CAPTCHA-gated phish at the end of August 2025, hit an eight-month low after falling 85% between December and February. While their volume nearly doubled in March, they remained well below late-2025 levels.
Line graph comparing monthly data usage for five file types. XLS shows a sharp increase in March, PDF declines steadily, HTML peaks in December, and DOC/DOCX and URL remain relatively low with slight fluctuations.
Figure 5. Monthly CAPTCHA-gated phishing volume by distribution method (Q1 2026)

Another notable shift in CAPTCHA-gated phishing attacks was the erosion of Tycoon2FA’s impact on the landscape. At the end of 2025, more than three-quarters of CAPTCHA-gated phishing sites were hosted on Tycoon2FA infrastructure. This share decreased significantly over the course of the first three months of 2026, falling to just 41% in March. This broadening of CAPTCHA-gated phishing sites being used by an increasing number of threat actors and phishing kits, combined with the overall surge in volume, indicates that this technique is becoming a more entrenched component of the phishing playbook rather than a specialty of a small number of tools.

Three-day campaign delivers CAPTCHA-gated phishing content using malicious SVG attachments

Between February 23 and February 25, 2026, a large, sustained campaign sent more than 1.2 million messages to users at more than 53,000 organizations in 23 countries. Messages in the campaign included a number of different themes, including an important 401K update, a credit hold warning, a question about a received payment, a payment request for a past due invoice, and a voice message notification.

Many of the messages contained a fake confidentiality disclaimer to enhance the credibility of the messages and provide a proactive excuse about why a recipient may have mistakenly received an email that may not be applicable to them.

A screenshot of an email confidentiality notice warning recipients against sharing the message with third parties without sender consent. The text emphasizes the message's intended recipient, prohibits unauthorized distribution, and clarifies that the email does not constitute a legally binding agreement.
Figure 6. Example fake confidentiality message used in February 23-25 phishing campaign

Attached to each message was an SVG file that was named to appropriately match the theme of the email. All the file names included a Base64-encoded version of the recipient’s email address. Example of file names used in the campaign include the following:

  • <Recipient Email Domain>_statements_inv_<Base64-encoded Email Address>.svg
  • 401K_copy_<Recipient Name>_<Base64-encoded Email Address>_241.svg
  • Check_2408_Payment_Copy_<Recipient First Name>_<Base64-encoded Email Address>_241.svg
  • INV#_1709612175_<Base64-encoded Email Address>.svg
  • Listen_(<Base64-encoded Email Address>).svg
  • PLAY_AUDIO_MESSAGE__<Recipient Name>_<Base64-encoded Email Address>_241.svg

If an attached SVG file was opened, the user’s browser would open locally and fetch content from one of the three following hostnames:

  • bouleversement.niovapahrm[.]com
  • haematogenesis.hvishay[.]com
  • ubiquitarianism.drilto[.]com

Initially, the user would be shown a “security check” CAPTCHA. Once the CAPTCHA had been successfully completed, the user would then be shown a fake sign-in page used to compromise their account credentials.

Malicious payloads

Credential phishing tightened its grip on the malicious payload landscape across Q1, growing from 89% of all payload-based attacks in January to 95% in February before settling at 94% in March. These credential phishing payloads either linked users to phishing pages or locally loaded spoofed sign-in screens on a user’s device. Traditional malware delivery continued its long-term decline, representing just 5–6% of payloads by the end of the quarter.

Pie chart showing distribution of malicious payloads: HTML (31%), PDF (28%), SVG (19%), DOC/DOCX (12%), and URL (10%).
Figure 7. Malicious payloads by file type (Q1 2026)

The most striking payload trend was the volatility across file types, driven by large campaigns that created dramatic week-to-week swings:

  • HTML attachments started Q1 as the leading file type (37% of payloads in January), fell to an annual low in February (-57%), then nearly tripled in March (+175%). This volatility was largely campaign-driven, with concentrated activity in the first half of January and the third week of March.
  • Malicious PDFs followed a steady upward trajectory, increasing 38% in February and another 50% in March to reach their highest monthly volume in over a year. By March, PDFs accounted for 29% of payloads, up from 19% in January.
  • ZIP/GZIP attachments were similarly volatile by nearly doubling in January (+94%), dropping 38% in February, then surging 79% in March. Threat actors commonly use ZIP files to circumvent Mark of the Web (MOTW) protections.
  • SVG files emerged briefly in February as a notable delivery method (with a 50% volume increase) before declining 32% in March, mirroring the pattern seen in CAPTCHA-gated phishing.
Line graph showing daily usage trends of five file formats (DOC/DOCX, HTML, PDF, SVG, and ZIP). HTML files exhibit the highest and most frequent spikes, reaching over 2 million, while other formats maintain lower, more stable usage with occasional peaks.
Figure 8. Daily malicious payload file type (Q1 2026)

Large-scale HTML phishing campaign hosts content on multiple PhaaS infrastructures

On March 17, 2026, Microsoft Threat Intelligence observed a massive phishing campaign that drove a significant surge in malicious HTML attachments during the month. The campaign involved more than 1.5 million confirmed malicious messages sent to over 179,000 organizations across 43 countries, accounting for approximately 7% of all malicious HTML attachments observed in March.

All messages in this campaign were likely sent using the same tool or service, which exhibited several distinct and highly consistent characteristics. Most notably, sender addresses across the campaign featured excessively long, keyword‑stuffed usernames that embedded URLs, tracking identifiers, and service references. These usernames were crafted to resemble legitimate transactional, billing, or document‑related notification senders. Examples of observed sender usernames include:

  • eReceipt_Payment_Alert_Noreply-/m939k6d7.r.us-west-2.awstrack.me/L0/%2F%2Fspectrumbusiness.net%2Fbilling%2F/2/010101989f2c1f29-ab5789bd-1426-4800-ae7d-877ea7f61d24-000000/LHnBIXX0VmCLVoXwNWtt23hGCdc=439/us02web.zoom.nl/j/81163775943?pwd=bLoo4JaWavsiTAuLWNoRsmbmALwjLB.1-qq8m2tzd
  • Center-=AAP1eU7NKykAABXNznVa8w___listenerId=AAP1eU7NKykAABXNznVa8w___aw_0_device.player_name=Chrome___aw_0_ivt.result=unknown___cbs=9901711___aw_0_azn.zposition=%5B%22undefined%22%5D___us_privacy=___aw_0_app.name=Second+Screen___externalClickUrl=otdk-takaki-h
  • DocExchange_Noreply-m939k6d7.r.us_west_2.awstrack.me/L0/%2F%2Fspectrumbusiness.net%2Fbilling%2F/2/010101989f2c1f29ab5789bd14264800ae7d877ea7f61d24000000/LHnBIXX0VmCLVoXwNWtt23hGCdc=439/us02web.zoom.nl/j/81163775943?pwd=bLoo4JaWavsiTAuLWNoRsmbmALwjLB.1-angie

The emails themselves contained little to no message body content. While subject lines varied, they consistently impersonated routine business and workflow notifications, including payment and remittance alerts (for example, Automated Clearing House (ACH), Electronic Funds Transfer (EFT), wire), invoice or aging statements, and e‑signature or document delivery requests. These subjects relied on urgency, approval language, and transactional framing to prompt recipients to review, sign, or access an attached document.

Each message included an HTML attachment with a file name aligned to the email’s theme. When opened, the HTML file launched locally on the recipient’s device and immediately redirected the user to an initial external staging page. This page performed basic screening and then redirected the user to a secondary landing page hosting the phishing content. On the final landing page, users were presented with a CAPTCHA challenge before being directed to a fraudulent sign‑in page designed to harvest account credentials.

Interestingly, although messages in this campaign shared common tooling, structure, and delivery characteristics, the infrastructure hosting the final phishing payload was linked to multiple different PhaaS providers. Most observed phishing endpoints were associated with Tycoon2FA, while additional activity was linked to Kratos (formerly Sneaky2FA) and EvilTokens infrastructure.

Business email compromise

Microsoft defines business email compromise (BEC) as a text-based attack targeting enterprise users that impersonates a trusted entity for the purpose of persuading a recipient into initiating a fraudulent financial transaction or sending the threat actor sensitive documents. These attacks fluctuated across Q1, totaling approximately 10.7 million attacks: rising 24% in January, dipping 8% in February, then surging 26% in March.

Line chart displays monthly BEC attack volume data for five months, with attacks starting high in November, dip in December, rise through January and February, and peak sharply in March to over 4 million attacks.
Figure 9. Monthly BEC attack volume (November 2025 – March 2026)

The composition of BEC attacks remained consistent throughout Q1. Generic outreach messages (like “Are you at your desk?”) accounted for 82–84% of initial contact emails each month, while explicit requests for specific financial transactions or documents represented just 9–10%. This pattern underscores that BEC operators overwhelmingly favor establishing a conversational rapport before making fraudulent requests, rather than leading with direct financial asks.

Within the smaller subset of explicit financial requests, two sub-categories showed notable movement. Payroll update requests grew 15% in February, reaching their highest volume in eight months, potentially reflecting tax season-related social engineering. Gift card requests fell 37% in February to their lowest level since July before rebounding sharply in March (+108%), though they still represented less than 3% of overall BEC messages. These fluctuations suggest that BEC operators adjust their specific financial pretexts seasonally while maintaining a consistent overall approach.

Pie chart displays BEC email content distribution for Q1 2026. Generic outreach contact dominates at 83.1%, followed by generic task request at 7.0%, payroll update at 4.2%, invoice payment at 3.1%, gift card request at 2.2%, and other at 0.4%, with each segment color-coded and labeled.
Figure 10. Initial BEC email content by type (Q1 2026)

Defending against email threats

Microsoft recommends the following mitigations to reduce the impact of this threat.

  • Review the recommended settings for Exchange Online Protection and Microsoft Defender for Office 365 to ensure your organization has established essential defenses and knows how to monitor and respond to threat activity.
  • Invest in user awareness training and phishing simulations. Attack simulation training in Microsoft Defender for Office 365, which also includes simulating phishing messages in Microsoft Teams, is one approach to running realistic attack scenarios in your organization.
  • Enable Zero-hour auto purge (ZAP) in Defender for Office 365 to quarantine sent mail in response to newly acquired threat intelligence and retroactively neutralize malicious phishing, spam, or malware messages that have already been delivered to mailboxes.
  • Responders could also manually check for and purge unwanted emails containing URLs and/or Subject fields that are similar, but not identical, to those of known bad messages. Investigate malicious email that was delivered in Microsoft 365 and use Threat Explorer to find and delete phishing emails.
  • Turn on Safe Links and Safe Attachments in Microsoft Defender for Office 365.
  • Enable network protection in Microsoft Defender for Endpoint.
  • Encourage users to use Microsoft Edge and other web browsers that support Microsoft Defender SmartScreen, which identifies and blocks malicious websites, including phishing sites, scam sites, and sites that host malware.
  • Enable password-less authentication methods (for example, Windows Hello, FIDO keys, or Microsoft Authenticator) for accounts that support password-less. For accounts that still require passwords, use authenticator apps like Microsoft Authenticator for MFA. Refer to this article for the different authentication methods and features.
  • Configure automatic attack disruption in Microsoft Defender XDR. Automatic attack disruption is designed to contain attacks in progress, limit the impact on an organization’s assets, and provide more time for security teams to remediate the attack fully.

Microsoft Defender detections

Microsoft Defender customers can refer to the list of applicable detections below. Microsoft Defender coordinates detection, prevention, investigation, and response across endpoints, identities, email, apps to provide integrated protection against attacks like the threat discussed in this blog.

Microsoft Defender for Endpoint

The following alert might indicate threat activity associated with this threat. The alert, however, can be triggered by unrelated threat activity.

  • Suspicious activity likely indicative of a connection to an adversary-in-the-middle (AiTM) phishing site

Microsoft Defender for Office 365

The following alerts might indicate threat activity associated with this threat. These alerts, however, can be triggered by unrelated threat activity.

  • A potentially malicious URL click was detected
  • A user clicked through to a potentially malicious URL
  • Suspicious email sending patterns detected
  • Email messages containing malicious URL removed after delivery
  • Email messages removed after delivery
  • Email reported by user as malware or phish

Microsoft Security Copilot

Microsoft Security Copilot is embedded in Microsoft Defender and provides security teams with AI-powered capabilities to summarize incidents, analyze files and scripts, summarize identities, use guided responses, and generate device summaries, hunting queries, and incident reports.

Customers can also deploy AI agents, including the following Microsoft Security Copilot agents, to perform security tasks efficiently:

Security Copilot is also available as a standalone experience where customers can perform specific security-related tasks, such as incident investigation, user analysis, and vulnerability impact assessment. In addition, Security Copilot offers developer scenarios that allow customers to build, test, publish, and integrate AI agents and plugins to meet unique security needs.

Threat intelligence reports

Microsoft Defender XDR customers can use the following Threat Analytics reports in the Defender portal (requires license for at least one Defender XDR product) to get the most up-to-date information about the threat actor, malicious activity, and techniques discussed in this blog. These reports provide intelligence, protection information, and recommended actions to prevent, mitigate, or respond to associated threats found in customer environments.

Microsoft Defender XDR threat analytics

Microsoft Security Copilot customers can also use the Microsoft Security Copilot integration in Microsoft Defender Threat Intelligence, either in the Security Copilot standalone portal or in the embedded experience in the Microsoft Defender portal to get more information about this threat actor.

Learn more

For the latest security research from the Microsoft Threat Intelligence community, check out the Microsoft Threat Intelligence Blog.

To get notified about new publications and to join discussions on social media, follow us on LinkedIn, X (formerly Twitter), and Bluesky.

To hear stories and insights from the Microsoft Threat Intelligence community about the ever-evolving threat landscape, listen to the Microsoft Threat Intelligence podcast.

The post Email threat landscape: Q1 2026 trends and insights appeared first on Microsoft Security Blog.

Best of the Worst: Five Attacks That Looked Broken (and Worked)

25 de Abril de 2026, 08:38

I skipped last week's roundup. Holiday weekend, family stuff, the usual. So this is a two-week-ish view of what we've published in the Threat Intelligence series since Edition 03 dropped on April 13.

The post Best of the Worst: Five Attacks That Looked Broken (and Worked) appeared first on Security Boulevard.

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Containing a domain compromise: How predictive shielding shut down lateral movement

In identity-based attack campaigns, any initial access activity can turn an already serious intrusion into a critical incident once it allows a threat actor to obtain domain-administration rights. At that point, the attacker effectively controls the Active Directory domain: they can change group memberships and Access Control Lists (ACLs), mint Kerberos tickets, replicate directory secrets, and push policy through mechanisms like Group Policy Objects (GPOs), among others.

What makes domain compromise especially challenging is how quickly it could happen: in many real-world cases, domain-level credentials are compromised immediately following the very first access, and once these credentials are exposed, they’re often abused immediately, well before defenders can fully scope what happened. Apart from this speed gap, responding to this type of compromise could also prove difficult. For one, incident responders can’t just simply “turn off” domain controllers, service accounts, or identity infrastructure and core services without risking business continuity. In addition, because compromised credential artifacts can spread fast and be replayed to expand access, restoring the identity infrastructure back to a trusted state usually means taking steps (for example, krbtgt rotation, GPO cleanup, and ACL validation) that could take additional time and effort in an already high-pressure situation.

These challenges highlight the need for a more proactive approach in disrupting and containing credential-based attacks as they happen. Microsoft Defender’s predictive shielding capability in automatic attack disruption helps address this need. Its ability to predict where attacks will pivot next and apply just in time hardening actions to  block credential abuse—including those targeting high-privilege accounts like domain admins—and lateral movement at near-real-time speed, shifting the advantageto the defenders.

Previously, we discussed how predictive shielding was able to disrupt a human-operated ransomware incident. In this blog post, we take a look at a real-world Active Directory domain compromise that illustrates the critical inflection point when a threat actor achieves domain -level control. We walk through the technical details of the incident to highlight attacker tradecraft, the operational challenges defenders face after domain compromise, and the value of proactive, exposure-based containment that predictive shielding provides.

Predictive shielding overview

Predictive shielding is a capability in Microsoft Defender’s automatic attack disruption that helps stop the spread of identity-based attacks, before an attacker fully operationalizes stolen credentials. Instead of waiting for an account to be observed doing something malicious, predictive shielding focuses on moments when credentials are likely exposed: when Defender sees high-confidence signals of credential theft activity on a device, it can proactively restrict the accounts that might have been exposed there.

Essentially, predictive shielding works as follows:

  • Defender detects post-breach activity strongly associated with credential exposure on a device.
  • It evaluates which high-privilege identities were likely exposed in that context.
  • It applies containment to those identities to reduce the attacker’s ability to pivot, limiting lateral movement paths and high-impact identity operations while the incident is being investigated and remediated. The intent is to close the “speed gap” where attackers can reuse newly exposed credentials faster than responders can scope, reset, and clean up.

This capability is available as an out-of-the-box enhancement for Microsoft Defender for Endpoint P2 customers who meet the Microsoft Defender prerequisites.

The following section revisits a real-world domain compromise that showcases how attack disruption and predictive shielding changed the outcome by acting on exposure, rather than just observed abuse. Interestingly, this case happened just as we’re rolling out the predictive shielding, so you can see the changes in both attacker tradecraft and the detection and response actions before and after this capability was deployed.

Attack chain overview

In June 2025, a public sector organization was targeted by a threat actor. This threat actor progressed methodically: initial exploitation, local escalation, directory reconnaissance, credential access, and expansion into Microsoft Exchange and identity infrastructure.  

Figure 1. Attack diagram of the domain compromise.

Initial entry: Pre-domain compromise

The campaign began at the edge: a file-upload flaw in an internet-facing Internet Information Services (IIS) server was abused to plant and launch a web shell. The attacker then simultaneously performed various reconnaissance activities using the compromised account through the web shell and escalated their privileges to NT AUTHORITY\SYSTEM by abusing a Potato-class token impersonation primitive (for example, BadPotato).

The discovery commands observed in the attack include the following example:

Using the compromised IIS service account, the attacker attempted to reset the passwords of high-impact identities, a common technique used to gain control over accounts without performing credential dumping. The attacker also deployed Mimikatz to dump logon secrets (for example, MSV, LSASS, and SAM), harvesting credentials that are exposed on the device.

Had predictive shielding been released at this point, automated restrictions on exposed accounts could have stopped the intrusion before it expanded beyond the single-host foothold. However, at the time of the incident, this capability hasn’t been deployed to customers yet.

Key takeaway: At this stage of an attack, it’s important to keep the containment host‑scoped. Defenders should prioritize blocking credential theft and stopping escalation before it reaches the identity infrastructure.

First pivot: Directory credential materialization and Exchange delegation

Within 24 hours, the attacker abused privileged accounts and remotely created a scheduled task on a domain controller. The task initiated NTDS snapshot activity and packaged the output using makecab.exe, enabling offline access to directory credential material that’s suitable for abusing credentials at scale:

Because the first malicious action by the abused account already surfaced the entire Active Directory credentials, stopping its path for total domain compromise was no longer feasible.

The threat actor then planted a Godzilla web shell on Exchange Server, used a privileged context to enumerate accounts with ApplicationImpersonation role assignments, and granted full access to a delegated principal across mailboxes using Add‑MailboxPermission. This access allowed the threat actor to read and manipulate all mailbox contents.

The attack also used Impacket’s atexec.py to enumerate the role assignments remotely. Its use triggered the attack disruption capability in Defender, revoking the account sessions of an admin account and blocking it from further use.

Following the abused account’s disruption, the attacker attempted several additional actions, such as resetting the disrupted account’s and other accounts’ passwords. They also attempted to dump credentials of a Veeam backup device.

Key takeaway: This pivot is a turning point. Once directory credentials and privileged delegation are in play, the scope and impact of an incident expand fast. Defenders should prioritize protecting domain controllers, privileged identities, and authentication paths.

Scale and speed: Tool return, spraying, and lateral movement

Weeks later, the threat actor returned with an Impacket tooling (for example, secretsdump and PsExec) that resulted in repeated disruptions by Defender against the abused accounts that they used. These disruptions forced the attacker to pivot to other compromised accounts and exhaust their resources.

Following Defender’s disruptions, the threat actor then launched a broad password spray from the initially compromised IIS server, unlocking access to at least 14 servers through password reuse. They also attempted remote credential dumping against a couple of domain controllers and an additional IIS server using multiple domain and service principals.

Key takeaway: Even though automatic attack disruption acted right away, the attacker already possessed multiple credentials due to the previous large-scale credential dumping. This scenario showcases the race to detect and disrupt credential abuse and is the reason we’re introducing predictive shielding to preemptively disrupt exposed accounts at risk.

Predictive shielding breaks the chain: Exposure-centric containment

In the second phase of the attack, we activated predictive shielding. When exposure signals surfaced (for example, credential dumping attempts and replay from compromised hosts), automated containment blocked new sign-in attempts and interactive pivots not only for the abused accounts, but also for context-linked identities that are active on the same compromised surfaces.

Attack disruption contained high-privileged principals to prevent these accounts from being abused. Crucially, when a high-tier Enterprise or Schema Admin credential was exposed, predictive shielding contained it pre-abuse, preventing what would normally become a catastrophic escalation.

Second pivot: Alternative paths to new credentials

With high-value identities pre-contained, the threat actor pivoted to exploiting Apache Tomcat servers. They compromised three Tomcat servers, dropped the Godzilla web shell, and launched the PowerShell-based Invoke-Mimikatz command to harvest additional credentials. At one point, the attacker operated under Schema Admin:

They then used Impacket WmiExec to access Microsoft Entra Connect servers and attempt to extract Entra Connect synchronization credentials. The account used for this pivot was later contained, limiting further lateral movement.

Last attempts and shutdown

In the final phase of the attack, the threat actor attempted a full LSASS dump on a file sharing server using comsvcs.dll MiniDump under a domain user account, followed by additional NTDS activity:

Attack disruption in Defender repeatedly severed sessions and blocked new sign-ins made by the threat actor. On July 28, 2025, the attack campaign lost momentum and stopped.

How predictive shielding changed the outcome

Before compromising a domain, attackers are mostly constrained by the hosts they control. However, even a small set of exposed credentials could remove their constraints and give them broad access through privileged authentication and delegated pathways. The blast radius spreads fast, time pressure spikes, and containment decisions become riskier because identity infrastructure and high-privilege accounts are production dependencies.

The incident we revisited earlier almost followed a similar pattern. It unfolded while predictive shielding was still being launched, so the automated predictive containment capability only became active at the midway of the attack campaign. During the attack’s first stages, the threat actor had room to scale—they returned with new tooling, launched a broad password spray attack, and expanded access across multiple servers. They also attempted remote credential dumping against domain controllers and servers.

When predictive shielding went live, it helped shift the story and we then saw the change of pace—instead of reacting to each newly abused account, the capability allowed Defender to act preemptively and turn credential theft attempts into blocked pivots. Defender was able to block new sign-ins and interactive pivots, not just for the single abused account, but also for context-linked identities that were active on the same compromised surfaces.

With high-value identities pre-contained, the adversary shifted tradecraft and chased other credential sources, but each of their subsequent attempts triggered targeted containment that limited their lateral reach until they lost momentum and stopped. How this incident concluded is the operational “tell” that containment is working, in that once privileged pivots get blocked, threat actors often hunt for alternate credential sources, and defenses must continue following the moving blast radius.

As predictive shielding matures, it will continue to expand its prediction logic and context-linked identities.

MITRE ATT&CK® techniques observed

The following table maps observed behaviors to ATT&CK®.

Tactics shown are per technique definition.

Tactic(s)Technique IDTechnique nameObserved details
Initial AccessT1190Exploit Public-Facing ApplicationExploited a file-upload vulnerability in an IIS server to drop a web shell.
PersistenceT1505.003Server Software Component: Web ShellDeployed web shells for persistent access.
ExecutionT1059.001Command and Scripting Interpreter: PowerShellUsed PowerShell for Exchange role queries, mailbox permission changes, and Invoke-Mimikatz.
Privilege EscalationT1068Exploitation for Privilege EscalationUsed BadPotato to escalate to SYSTEM on an IIS server.
Credential AccessT1003.001OS Credential Dumping: LSASS MemoryDumped LSASS using Mimikatz and comsvcs.dll MiniDump.
Credential AccessT1003.003OS Credential Dumping: NTDSPerformed NTDS-related activity using ntdsutil snapshot/IFM workflows on a domain controller.
Execution; Persistence; Privilege EscalationT1053.005Scheduled Task/Job: Scheduled TaskCreated remote scheduled tasks to execute under SYSTEM on a domain controller.
DiscoveryT1087.002Account Discovery: Domain AccountEnumerated domain groups and accounts using net group and AD Explorer.
Lateral MovementT1021.002Remote Services: SMB/Windows Admin SharesUsed admin shares/SMB-backed tooling (for example, PsExec) for lateral movement.
Lateral MovementT1021.003Remote Services: Windows Remote ManagementUsed WmiExec against Microsoft Entra Connect servers.
Credential AccessT1110.003Brute Force: Password SprayingPerformed password spraying leading to access across at least 14 servers.
CollectionT1114.002Email Collection: Remote Email CollectionExpanded mailbox access broadly through impersonation or permission changes.
Command and ControlT1071.001Application Layer Protocol: Web ProtocolsWeb shells communicated over HTTP/S.
Defense EvasionT1070.004Indicator Removal on Host: File DeletionUsed cleanup scripts (for example, del.bat) to remove dump artifacts.
Persistence; Privilege EscalationT1098Account ManipulationManipulated permissions and roles to expand access and sustain control.
Credential AccessT1078Valid AccountsReused compromised service and domain accounts for access and lateral movement.

Learn more

For more information about automatic attack disruption and predictive shielding, see the following Microsoft Learn articles:

The post Containing a domain compromise: How predictive shielding shut down lateral movement appeared first on Microsoft Security Blog.

Dissecting Sapphire Sleet’s macOS intrusion from lure to compromise

Executive summary

Microsoft Threat Intelligence uncovered a macOS‑focused cyber campaign by the North Korean threat actor Sapphire Sleet that relies on social engineering rather than software vulnerabilities. By impersonating a legitimate software update, threat actors tricked users into manually running malicious files, allowing them to steal passwords, cryptocurrency assets, and personal data while avoiding built‑in macOS security checks. This activity highlights how convincing user prompts and trusted system tools can be abused, and why awareness and layered security defenses remain critical.


Microsoft Threat Intelligence identified a campaign by North Korean state actor Sapphire Sleet demonstrating new combinations of macOS-focused execution patterns and techniques, enabling the threat actor to compromise systems through social engineering rather than software exploitation. In this campaign, Sapphire Sleet takes advantage of user‑initiated execution to establish persistence, harvest credentials, and exfiltrate sensitive data while operating outside traditional macOS security enforcement boundaries. While the techniques themselves are not novel, this analysis highlights execution patterns and combinations that Microsoft has not previously observed for this threat actor, including how Sapphire Sleet orchestrates these techniques together and uses AppleScript as a dedicated, late‑stage credential‑harvesting component integrated with decoy update workflows.

After discovering the threat, Microsoft shared details of this activity with Apple as part of our responsible disclosure process. Apple has since implemented updates to help detect and block infrastructure and malware associated with this campaign. We thank the Apple security team for their collaboration in addressing this activity and encourage macOS users to keep their devices up to date with the latest security protections.

This activity demonstrates how threat actors continue to rely on user interaction and trusted system utilities to bypass macOS platform security protections, rather than exploiting traditional software vulnerabilities. By persuading users to manually execute AppleScript or Terminal‑based commands, Sapphire Sleet shifts execution into a user‑initiated context, allowing the activity to proceed outside of macOS protections such as Transparency, Consent, and Control (TCC), Gatekeeper, quarantine enforcement, and notarization checks. Sapphire Sleet achieves a highly reliable infection chain that lowers operational friction and increases the likelihood of successful compromise—posing an elevated risk to organizations and individuals involved in cryptocurrency, digital assets, finance, and similar high‑value targets that Sapphire Sleet is known to target.

In this blog, we examine the macOS‑specific attack chain observed in recent Sapphire Sleet intrusions, from initial access using malicious .scpt files through multi-stage payload delivery, credential harvesting using fake system dialogs, manipulation of the macOS TCC database, persistence using launch daemons, and large-scale data exfiltration. We also provide actionable guidance, Microsoft Defender detections, hunting queries, and indicators of compromise (IOCs) to help defenders identify similar threats and strengthen macOS security posture.

Sapphire Sleet’s campaign lifecycle

Initial access and social engineering

Sapphire Sleet is a North Korean state actor active since at least March 2020 that primarily targets the finance sector, including cryptocurrency, venture capital, and blockchain organizations. The primary motivation of this actor is to steal cryptocurrency wallets to generate revenue, and target technology or intellectual property related to cryptocurrency trading and blockchain platforms.

Recent campaigns demonstrate expanded execution mechanisms across operating systems like macOS, enabling Sapphire Sleet to target a broader set of users through parallel social engineering workflows.

Sapphire Sleet operates a well‑documented social engineering playbook in which the threat actor creates fake recruiter profiles on social media and professional networking platforms, engages targets in conversations about job opportunities, schedules a technical interview, and directs targets to install malicious software, which is typically disguised as a video conferencing tool or software developer kit (SDK) update.

In this observed activity, the target was directed to download a file called Zoom SDK Update.scpt—a compiled AppleScript that opens in macOS Script Editor by default. Script Editor is a trusted first-party Apple application capable of executing arbitrary shell commands using the do shell script AppleScript command.

Lure file and Script Editor execution

Flowchart illustrating Sapphire Sleet targeting users with a fake Zoom Support meeting invite, leading to the user joining the meeting, downloading a malicious AppleScript file, and executing the script via Script Editor.
Figure 1. Initial access: The .scpt lure file as seen in macOS Script Editor

The malicious Zoom SDK Update.scpt file is crafted to appear as a legitimate Zoom SDK update when opened in the macOS Script Editor app, beginning with a large decoy comment block that mimics benign upgrade instructions and gives the impression of a routine software update. To conceal its true behavior, the script inserts thousands of blank lines immediately after this visible content, pushing the malicious logic far below the scrollable view of the Script Editor window and reducing the likelihood that a user will notice it.

Hidden beneath this decoy, the script first launches a harmless looking command that invokes the legitimate macOS softwareupdate binary with an invalid parameter, an action that performs no real update but launches a trusted Apple‑signed process to reinforce the appearance of legitimacy. Following this, the script executes its malicious payload by using curl to retrieve threat actor‑controlled content and immediately passes the returned data to osascript for execution using the run script result instruction. Because the content fetched by curl is itself a new AppleScript, it is launched directly within the Script Editor context, initiating a payload delivery in which additional stages are dynamically downloaded and executed.

Screenshot of a code editor showing a script for updating Zoom Meeting SDK with comments about a new Zoom Web App release and instructions for manual SDK upgrade. The script includes a URL for SDK setup, a shell command to update software, and a highlighted note indicating presence of a malicious payload hidden below the visible editor area.
Figure 2. The AppleScript lure with decoy content and payload execution

Execution and payload delivery

Cascading curl-to-osascript execution

When the user opens the Zoom SDK Update.scpt file, macOS launches the file in Script Editor, allowing Sapphire Sleet to transition from a single lure file to a multi-stage, dynamically fetched payload chain. From this single process, the entire attack unfolds through a cascading chain of curl commands, each fetching and executing progressively more complex AppleScript payloads. Each stage uses a distinct user-agent string as a campaign tracking identifier.

Flowchart diagram illustrating a multi-stage malware attack process starting from a script editor executing various curl commands and AppleScripts, leading to backdoor deployments along with a credential harvester and host monitoring component.
Figure 3. Process tree showing cascading execution from Script Editor

The main payload fetched by the mac-cur1 user agent is the attack orchestrator. Once executed within the Script Editor, it performs immediate reconnaissance, then kicks off parallel operations using additional curl commands with different user-agent strings.

Note the URL path difference: mac-cur1 through mac-cur3 fetch from /version/ (AppleScript payloads piped directly to osascript for execution), while mac-cur4 and mac-cur5 fetch from /status/ (ZIP archives containing compiled macOS .app bundles).

The following table summarizes the curl chain used in this campaign.

User agentURL pathPurpose
mac-cur1/fix/mac/update/version/Main orchestrator (piped to osascript) beacon. Downloads com.apple.cli host monitoringcomponent and services backdoor
mac-cur2/fix/mac/update/version/Invokes curl with mac-cur4 which downloads credential harvester systemupdate.app
mac-cur3/fix/mac/update/version/TCC bypass + data collection + exfiltration (wallets, browser, keychains, history, Apple Notes, Telegram)
mac-cur4/fix/mac/update/status/Downloads credential harvester systemupdate.app (ZIP)
mac-cur5/fix/mac/update/status/Downloads decoy completion prompt softwareupdate.app (ZIP)
Screenshot of a script editor displaying a Zoom SDK update script with process ID 10015. The script includes multiple cURL commands, Rosetta check, and a main payload section indicating potential malicious activity branching from the execution point.
Figure 4. The curl chain showing user-agent strings and payload routing

Reconnaissance and C2 registration

After execution, the malware next identifies and registers the compromised device with Sapphire Sleet infrastructure. The malware starts by collecting basic system details such as the current user, host name, system time, and operating system install date. This information is used to uniquely identify the compromised device and track subsequent activity.

The malware then registers the compromised system with its command‑and‑control (C2) infrastructure. The mid value represents the device’s universally unique identifier (UUID), the did serves as a campaign‑level tracking identifier, and the user field combines the system host name with the device serial number to uniquely label the targeted user.

Screenshot of a terminal command using curl to send a POST request with JSON data to an API endpoint. The JSON payload includes fields like mid, did, user, osVersion, timezone, installdate, and proclist, with several values redacted for privacy.
Figure 5. C2 registration with device UUID and campaign identifier

Host monitoring component: com.apple.cli

The first binary deployed is a host monitoring component called com.apple.cli—a ~5 MB Mach-O binary disguised with an Apple-style naming convention.

The mac-cur1 payload spawns an osascript that downloads and launches com.apple.cli:

Screenshot of a code snippet showing a script designed to execute shell commands for downloading and running a payload, including setting usernames and handling errors.
Figure 6. com.apple.cli deployment using osascript

The host monitoring component repeatedly executes a series of system commands to collect environment and runtime information, including the macOS version (sw_vers), the current system time (date -u), and the underlying hardware model (sysctl hw.model). It then runs ps aux in a tight loop to capture a full, real‑time list of running processes.

During execution, com.apple.cli performs host reconnaissance while maintaining repeated outbound connectivity to the threat actor‑controlled C2 endpoint 83.136.208[.]246:6783. The observed sequencing of reconnaissance activity and network communication is consistent with staging for later operational activity, including privilege escalation, and exfiltration.

In parallel with deploying com.apple.cli, the mac-cur1 orchestrator also deploys a second component, the services backdoor, as part of the same execution flow; its role in persistence and follow‑on activity is described later in this blog.

Credential access

Credential harvester: systemupdate.app

After performing reconnaissance, the mac-cur1 orchestrator begins parallel operations. During the mac‑cur2 stage of execution (independent from the mac-cur1 stage), Sapphire Sleet delivers an AppleScript payload that is executed through osascript. This stage is responsible for deploying the credential harvesting component of the attack.

Before proceeding, the script checks for the presence of a file named .zoom.log on the system. This file acts as an infection marker, allowing Sapphire Sleet to determine whether the device has already been compromised. If the marker exists, deployment is skipped to avoid redundant execution across sessions.

If the infection marker is not found, the script downloads a compressed archive through the mac-cur4 user agent that contains a malicious macOS application named (systemupdate.app), which masquerades as the legitimate system update utility by the same name. The archive is extracted to a temporary location, and the application is launched immediately.

When systemupdate.app launches, the user is presented with a native macOS password dialog that is visually indistinguishable from a legitimate system prompt. The dialog claims that the user’s password is required to complete a software update, prompting the user to enter their credentials.

After the user enters their password, the malware performs two sequential actions to ensure the credential is usable and immediately captured. First, the binary validates the entered password against the local macOS authentication database using directory services, confirming that the credential is correct and not mistyped. Once validation succeeds, the verified password is immediately exfiltrated to threat actor‑controlled infrastructure using the Telegram Bot API, delivering the stolen credential directly to Sapphire Sleet.

Figure 7. Password popup given by fake systemupdate.app

Decoy completion prompt: softwareupdate.app

After credential harvesting is completed using systemupdate.app, Sapphire Sleet deploys a second malicious application named softwareupdate.app, whose sole purpose is to reinforce the illusion of a legitimate update workflow. This application is delivered during a later stage of the attack using the mac‑cur5 user‑agent. Unlike systemupdate.app, softwareupdate.app does not attempt to collect credentials. Instead, it displays a convincing “system update complete” dialog to the user, signaling that the supposed Zoom SDK update has finished successfully. This final step closes the social engineering loop: the user initiated a Zoom‑themed update, was prompted to enter their password, and is now reassured that the process completed as expected, reducing the likelihood of suspicion or further investigation.

Persistence

Primary backdoor and persistence installer: services binary

The services backdoor is a key operational component in this attack, acting as the primary backdoor and persistence installer. It provides an interactive command execution channel, establishes persistence using a launch daemon, and deploys two additional backdoors. The services backdoor is deployed through a dedicated AppleScript executed as part of the initial mac‑cur1 payload that also deployed com.apple.cli, although the additional backdoors deployed by services are executed at a later stage.

During deployment, the services backdoor binary is first downloaded using a hidden file name (.services) to reduce visibility, then copied to its final location before the temporary file is removed. As part of installation, the malware creates a file named auth.db under ~/Library/Application Support/Authorization/, which stores the path to the deployed services backdoor and serves as a persistent installation marker. Any execution or runtime errors encountered during this process are written to /tmp/lg4err, leaving behind an additional forensic artifact that can aid post‑compromise investigation.

Screenshot of a code snippet written in a scripting language, focused on setting variables, file paths, and executing shell commands for downloading and managing files.
Figure 8. Services backdoor deployment using osascript

Unlike com.apple.cli, the services backdoor uses interactive zsh shells (/bin/zsh -i) to execute privileged operations. The -i flag creates an interactive terminal context, which is required for sudo commands that expect interactive input.

Screenshot of terminal commands and script annotations related to installing and configuring persistence for icloudz malware. Commands include environment checks, anti-sleep measures, OS version beacon, credential harvester deletion, self-copy creation, and five persistence installation steps with file paths, permissions, and launchctl commands.
Figure 9. Interactive zsh shell execution by the services backdoor

Additional backdoors: icloudz and com.google.chromes.updaters

Of the additional backdoors deployed by services, the icloudz backdoor is a renamed copy of the previously deployed services backdoor and shares the same SHA‑256 hash, indicating identical underlying code. Despite this, it is executed using a different and more evasive technique. Although icloudz shares the same binary as .services, it operates as a reflective code loader—it uses the macOS NSCreateObjectFileImageFromMemory API to load additional payloads received from its C2 infrastructure directly into memory, rather than writing them to disk and executing them conventionally.

The icloudz backdoor is stored at ~/Library/Application Support/iCloud/icloudz, a location and naming choice intended to resemble legitimate iCloud‑related artifacts. Once loaded into memory, two distinct execution waves are observed. Each wave independently initializes a consistent sequence of system commands: existing caffeinate processes are stopped, caffeinate is relaunched using nohup to prevent the system from sleeping, basic system information is collected using sw_vers and sysctl -n hw.model, and an interactive /bin/zsh -i shell is spawned. This repeated initialization suggests that the component is designed to re‑establish execution context reliably across runs.

From within the interactive zsh shell, icloudz deploys an additional (tertiary) backdoor, com.google.chromes.updaters, to disk at ~/Library/Google/com.google.chromes.updaters. The selected directory and file name closely resemble legitimate Google application data, helping the file blend into the user’s Home directory and reducing the likelihood of casual inspection. File permissions are adjusted; ownership is set to allow execution with elevated privileges, and the com.google.chromes.updaters binary is launched using sudo.

To ensure continued execution across reboots, a launch daemon configuration file named com.google.webkit.service.plist is installed under /Library/LaunchDaemons. This configuration causes icloudz to launch automatically at system startup, even if no user is signed in. The naming convention deliberately mimics legitimate Apple and Google system services, further reducing the chance of detection.

The com.google.chromes.updaters backdoor is the final and largest component deployed in this attack chain, with a size of approximately 7.2 MB. Once running, it establishes outbound communication with threat actor‑controlled infrastructure, connecting to the domain check02id[.]com over port 5202. The process then enters a precise 60‑second beaconing loop. During each cycle, it executes minimal commands such as whoami to confirm the execution context and sw_vers -productVersion to report the operating system version. This lightweight heartbeat confirms the process remains active, is running with elevated privileges, and is ready to receive further instructions.

Privilege escalation

TCC bypass: Granting AppleEvents permissions

Before large‑scale data access and exfiltration can proceed, Sapphire Sleet must bypass macOS TCC protections. TCC enforces user consent for sensitive inter‑process interactions, including AppleEvents, the mechanism required for osascript to communicate with Finder and perform file-level operations. The mac-cur3 stage silently grants itself these permissions by directly manipulating the user-level TCC database through the following sequence.

The user-level TCC database (~/Library/Application Support/com.apple.TCC/TCC.db) is itself TCC-protected—processes without Full Disk Access (FDA) cannot read or modify it. Sapphire Sleet circumvents this by directing Finder, which holds FDA by default on macOS,  to rename the com.apple.TCC folder. Once renamed, the TCC database file can be copied to a staging location by a process without FDA.

Sapphire Sleet then uses sqlite3 to inject a new entry into the database’s access table. This entry grants /usr/bin/osascript permission to send AppleEvents to com.apple.finder and includes valid code-signing requirement (csreq) blobs for both binaries, binding the grant to Apple-signed executables. The authorization value is set to allowed (auth_value=2) with a user-set reason (auth_reason=3), ensuring no user prompt is triggered. The modified database is then copied back into the renamed folder, and Finder restores the folder to its original name. Staging files are deleted to reduce forensic traces.

Screenshot of a code snippet showing an SQLite3 command to insert data into an access table with columns for service, client, client_type, auth_value, and other attributes.
Figure 10. Overwriting original TCC database with modified version

Collection and exfiltration

With TCC bypassed, credentials stolen, and backdoors deployed, Sapphire Sleet launches the next phase of attack: a 575-line AppleScript payload that systematically collects, stages, compresses, and exfiltrates seven categories of data.

Exfiltration architecture

Every upload follows a consistent pattern and is executed using nohup, which allows the command to continue running in the background even if the initiating process or Terminal session exits. This ensures that data exfiltration can complete reliably without requiring the threat actor to maintain an active session on the system.

The auth header provides the upload authorization token, and the mid header ties the upload to the compromised device’s UUID.

Screenshot of a terminal window showing a shell command sequence for zipping and uploading a file. Commands include compressing a directory, removing temporary files, and using curl with headers for authentication and file upload to a specified IP address and port.
Figure 11. Exfiltration upload pattern with nohup

Data collected during exfiltration

  • Host and system reconnaissance: Before bulk data collection begins, the script records basic system identity and hardware information. This includes the current username, system host name, macOS version, and CPU model. These values are appended to a per‑host log file and provide Sapphire Sleet with environmental context, hardware fingerprinting, and confirmation of the target system’s characteristics. This reconnaissance data is later uploaded to track progress and correlate subsequent exfiltration stages to a specific device.
  • Installed applications and runtime verification: The script enumerates installed applications and shared directories to build an inventory of the system’s software environment. It also captures a live process listing filtered for threat actor‑deployed components, allowing Sapphire Sleet to verify that earlier payloads are still running as expected. These checks help confirm successful execution and persistence before proceeding further.
  • Messaging session data (Telegram): Telegram Desktop session data is collected by copying the application’s data directories, including cryptographic key material and session mapping files. These artifacts are sufficient to recreate the user’s Telegram session on another system without requiring reauthentication. A second collection pass targets the Telegram App Group container to capture the complete local data set associated with the application.
  • Browser data and extension storage: For Chromium‑based browsers, including Chrome, Brave, and Arc, the script copies browser profiles and associated databases. This includes saved credentials, cookies, autofill data, browsing history, bookmarks, and extension‑specific storage. Particular focus is placed on IndexedDB entries associated with cryptocurrency wallet extensions, where wallet keys and transaction data are stored. Only IndexedDB entries matching a targeted set of wallet extension identifiers are collected, reflecting a deliberate and selective approach.
  • macOS keychain: The user’s sign-in keychain database is bundled alongside browser data. Although the keychain is encrypted, Sapphire Sleet has already captured the user’s password earlier in the attack chain, enabling offline decryption of stored secrets once exfiltrated.
  • Cryptocurrency desktop wallets: The script copies the full application support directories for popular cryptocurrency desktop wallets, including Ledger Live and Exodus. These directories contain wallet configuration files and key material required to access stored cryptocurrency assets, making them high‑value targets for exfiltration.
  • SSH keys and shell history: SSH key directories and shell history files are collected to enable potential lateral movement and intelligence gathering. SSH keys may provide access to additional systems, while shell history can reveal infrastructure details, previously accessed hosts, and operational habits of the targeted user.
  • Apple Notes: The Apple Notes database is copied from its application container and staged for upload. Notes frequently contain sensitive information such as passwords, internal documentation, infrastructure details, or meeting notes, making them a valuable secondary data source.
  • System logs and failed access attempts: System log files are uploaded directly without compression. These logs provide additional hardware and execution context and include progress markers that indicate which exfiltration stages have completed. Failed collection attempts—such as access to password manager containers that are not present on the system—are also recorded and uploaded, allowing Sapphire Sleet to understand which targets were unavailable on the compromised host.

Exfiltration summary

#Data categoryZIP nameUpload portEstimated sensitivity
1Telegram sessiontapp_<user>.zip8443Critical — session hijack
2Browser data + Keychainext_<user>.zip8443Critical — all passwords
3Ledger walletldg_<user>.zip8443Critical — crypto keys
4Exodus walletexds_<user>.zip8443Critical — crypto keys
5SSH + shell historyhs_<user>.zip8443High — lateral movement
6Apple Notesnt_<user>.zip8443Medium-High
7System loglg_<user> (no zip)8443Low — fingerprinting
8Recon logflog (no zip)8443Low — inventory
9CredentialsTelegram message443 (Telegram API)Critical — sign-in password

All uploads use the upload authorization token fwyan48umt1vimwqcqvhdd9u72a7qysi and the machine identifier 82cf5d92-87b5-4144-9a4e-6b58b714d599.

Defending against Sapphire Sleet intrusion activity

As part of a coordinated response to this activity, Apple has implemented platform-level protections to help detect and block infrastructure and malware associated with this campaign. Apple has deployed Apple Safe Browsing protections in Safari to detect and block malicious infrastructure associated with this campaign. Users browsing with Safari benefit from these protections by default. Apple has also deployed XProtect signatures to detect and block the malware families associated with this campaign—macOS devices receive these signature updates automatically.

Microsoft recommends the following mitigation steps to defend against this activity and reduce the impact of this threat:

  • Educate users about social engineering threats originating from social media and external platforms, particularly unsolicited outreach requesting software downloads, virtual meeting tool installations, or execution of terminal commands. Users should never run scripts or commands shared through messages, calls, or chats without prior approval from their IT or security teams.
  • Block or restrict the execution of .scpt (compiled AppleScript) files and unsigned Mach-O binaries downloaded from the internet. Where feasible, enforce policies that prevent osascript from executing scripts sourced from external locations.
  • Always inspect and verify files downloaded from external sources, including compiled AppleScript (.scpt) files. These files can execute arbitrary shell commands via macOS Script Editor—a trusted first-party Apple application—making them an effective and stealthy initial access vector.
  • Limit or audit the use of curl piped to interpreters (such as curl | osascript, curl | sh, curl | bash). Social engineering campaigns by Sapphire Sleet rely on cascading curl-to-interpreter chains to avoid writing payloads to disk. Organizations should monitor for and restrict piped execution patterns originating from non-standard user-agent strings.
  • Exercise caution when copying and pasting sensitive data such as wallet addresses or credentials from the clipboard. Always verify that the pasted content matches the intended source to avoid falling victim to clipboard hijacking or data tampering attacks.
  • Monitor for unauthorized modifications to the macOS TCC database. This campaign manipulates TCC.db to grant AppleEvents permissions to osascript without user consent—a prerequisite for the large-scale data exfiltration phase. Look for processes copying, modifying, or overwriting ~/Library/Application Support/com.apple.TCC/TCC.db.
  • Audit LaunchDaemon and LaunchAgent installations. This campaign installs a persistent launch daemon (com.google.webkit.service.plist) that masquerades as a legitimate Google or Apple service. Monitor /Library/LaunchDaemons/ and ~/Library/LaunchAgents/ for unexpected plist files, particularly those with com.google.* or com.apple.* naming conventions not belonging to genuine vendor software.
  • Protect cryptocurrency wallets and browser credential stores. This campaign targets nine specific crypto wallet extensions (Sui, Phantom, TronLink, Coinbase, OKX, Solflare, Rabby, Backpack) plus Bitwarden, and exfiltrates browser sign-in data, cookies, and keychain databases. Organizations handling digital assets should enforce hardware wallet policies and rotate browser-stored credentials regularly.
  • Encourage users to use web browsers that support Microsoft Defender SmartScreen like Microsoft Edge—available on macOS and various platforms—which identifies and blocks malicious websites, including phishing sites, scam sites, and sites that contain exploits and host malware.

Microsoft Defender for Endpoint customers can also apply the following mitigations to reduce the environmental attack surface and mitigate the impact of this threat and its payloads:

Microsoft Defender detection and hunting guidance

Microsoft Defender customers can refer to the list of applicable detections below. Microsoft Defender coordinates detection, prevention, investigation, and response across endpoints, identities, email, apps to provide integrated protection against attacks like the threat discussed in this blog.

Tactic Observed activity Microsoft Defender coverage 
Initial access– Malicious .scpt file execution (Zoom SDK Update lure)Microsoft Defender Antivirus
– Trojan:MacOS/SuspMalScript.C
– Trojan:MacOS/FlowOffset.A!dha
 
Microsoft Defender for Endpoint
– Sapphire Sleet actor activity
– Suspicious file or content ingress
Execution– Malicious osascript execution
– Cascading curl-to-osascript chains
– Malicious binary execution
Microsoft Defender Antivirus
– Trojan:MacOS/SuspMalScript.C
– Trojan:MacOS/SuspInfostealExec.C
– Trojan:MacOS/NukeSped.D
 
Microsoft Defender for Endpoint
– Suspicious file dropped and launched
– Suspicious script launched
– Suspicious AppleScript activity
– Sapphire Sleet actor activity
– Hidden file executed
Persistence– LaunchDaemon installation (com.google.webkit.service.plist)Microsoft Defender for Endpoint
– Suspicious Plist modifications
– Suspicious launchctl tool activity
Defense evasion– TCC database manipulation
– Reflective code loading (NSCreateObjectFileImageFromMemory)
Microsoft Defender for Endpoint
– Potential Transparency, Consent and Control bypass
– Suspicious database access
Credential access– Fake password dialog (systemupdate.app, softwareupdate.app)
– Keychain exfiltration
Microsoft Defender Antivirus
– Trojan:MacOS/PassStealer.D
– Trojan:MacOS/FlowOffset.D!dha
– Trojan:MacOS/FlowOffset.E!dha  

Microsoft Defender for Endpoint
– Suspicious file collection
Collection and exfiltration– Browser data, crypto wallets, Telegram session, SSH keys, Apple Notes theft
– Credential exfiltration using Telegram Bot API
Microsoft Defender Antivirus
– Trojan:MacOS/SuspInfostealExec.C
 
Microsoft Defender for Endpoint
– Enumeration of files with sensitive data
– Suspicious File Copy Operations Using CoreUtil
– Suspicious archive creation
– Remote exfiltration activity
– Possible exfiltration of archived data
Command and control– Mach-O backdoors beaconing to C2 (com.apple.cli, services, com.google.chromes.updaters)Microsoft Defender Antivirus
– Trojan:MacOS/NukeSped.D  
– Backdoor:MacOS/FlowOffset.B!dha
– Backdoor:MacOS/FlowOffset.C!dha
 
Microsoft Defender for Endpoint
– Sapphire Sleet actor activity  
– Network connection by osascript

Microsoft Security Copilot

Microsoft Security Copilot is embedded in Microsoft Defender and provides security teams with AI-powered capabilities to summarize incidents, analyze files and scripts, summarize identities, use guided responses, and generate device summaries, hunting queries, and incident reports.

Customers can also deploy AI agents, including the following Microsoft Security Copilot agents, to perform security tasks efficiently:

Security Copilot is also available as a standalone experience where customers can perform specific security-related tasks, such as incident investigation, user analysis, and vulnerability impact assessment. In addition, Security Copilot offers developer scenarios that allow customers to build, test, publish, and integrate AI agents and plugins to meet unique security needs.

Threat intelligence reports

Microsoft Defender XDR customers can use the following threat analytics reports in the Defender portal (requires license for at least one Defender XDR product) to get the most up-to-date information about the threat actor, malicious activity, and techniques discussed in this blog. These reports provide the intelligence, protection information, and recommended actions to prevent, mitigate, or respond to associated threats found in customer environments.

Microsoft Defender XDR threat analytics

Microsoft Security Copilot customers can also use the Microsoft Security Copilot integration in Microsoft Defender Threat Intelligence, either in the Security Copilot standalone portal or in the embedded experience in the Microsoft Defender portal to get more information about this threat actor.

Hunting queries

Microsoft Defender XDR

Microsoft Defender XDR customers can run the following advanced hunting queries to find related activity in their networks:

Suspicious osascript execution with curl piping

Search for curl commands piping output directly to osascript, a core technique in this Sapphire Sleet campaign’s cascading payload delivery chain.

DeviceProcessEvents
 | where Timestamp > ago(30d)
 | where FileName == "osascript" or InitiatingProcessFileName == "osascript"
 | where ProcessCommandLine has "curl" and ProcessCommandLine has_any ("osascript", "| sh", "| bash")
 | project Timestamp, DeviceId, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessCommandLine, InitiatingProcessFileName

Suspicious curl activity with campaign user-agent strings

Search for curl commands using user-agent strings matching the Sapphire Sleet campaign tracking identifiers (mac-cur1 through mac-cur5, audio, beacon).

DeviceProcessEvents
 | where Timestamp > ago(30d)
 | where FileName == "curl" or ProcessCommandLine has "curl"
 | where ProcessCommandLine has_any ("mac-cur1", "mac-cur2", "mac-cur3", "mac-cur4", "mac-cur5", "-A audio", "-A beacon")
 | project Timestamp, DeviceId, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine

Detect connectivity with known C2 infrastructure

Search for network connections to the Sapphire Sleet C2 domains and IP addresses used in this campaign.

let c2_domains = dynamic(["uw04webzoom.us", "uw05webzoom.us", "uw03webzoom.us", "ur01webzoom.us", "uv01webzoom.us", "uv03webzoom.us", "uv04webzoom.us", "ux06webzoom.us", "check02id.com"]);
 let c2_ips = dynamic(["188.227.196.252", "83.136.208.246", "83.136.209.22", "83.136.208.48", "83.136.210.180", "104.145.210.107"]);
 DeviceNetworkEvents
 | where Timestamp > ago(30d)
 | where RemoteUrl has_any (c2_domains) or RemoteIP in (c2_ips)
 | project Timestamp, DeviceId, DeviceName, RemoteUrl, RemoteIP, RemotePort, InitiatingProcessFileName, InitiatingProcessCommandLine

TCC database manipulation detection

Search for processes that copy, modify, or overwrite the macOS TCC database, a key defense evasion technique used by this campaign to grant unauthorized AppleEvents permissions.

DeviceFileEvents
 | where Timestamp > ago(30d)
 | where FolderPath has "com.apple.TCC" and FileName == "TCC.db"
 | where ActionType in ("FileCreated", "FileModified", "FileRenamed")
 | project Timestamp, DeviceId, DeviceName, ActionType, FolderPath, InitiatingProcessFileName, InitiatingProcessCommandLine

Suspicious LaunchDaemon creation masquerading as legitimate services

Search for LaunchDaemon plist files created in /Library/LaunchDaemons that masquerade as Google or Apple services, matching the persistence technique used by the services/icloudz backdoor.

DeviceFileEvents
 | where Timestamp > ago(30d)
 | where FolderPath startswith "/Library/LaunchDaemons/"
 | where FileName startswith "com.google." or FileName startswith "com.apple."
 | where ActionType == "FileCreated"
 | project Timestamp, DeviceId, DeviceName, FileName, FolderPath, InitiatingProcessFileName, InitiatingProcessCommandLine, SHA256

Malicious binary execution from suspicious paths

Search for execution of binaries from paths commonly used by Sapphire Sleet, including hidden Library directories, /private/tmp/, and user-specific Application Support folders.

DeviceProcessEvents
 | where Timestamp > ago(30d)
 | where FolderPath has_any (
     "Library/Services/services",
     "Application Support/iCloud/icloudz",
     "Library/Google/com.google.chromes.updaters",
     "/private/tmp/SystemUpdate/",
     "/private/tmp/SoftwareUpdate/",
     "com.apple.cli"
 )
 | project Timestamp, DeviceId, DeviceName, FileName, FolderPath, ProcessCommandLine, AccountName, SHA256

Credential harvesting using dscl authentication check

Search for dscl -authonly commands used by the fake password dialog (systemupdate.app) to validate stolen credentials before exfiltration.

DeviceProcessEvents
 | where Timestamp > ago(30d)
 | where FileName == "dscl" or ProcessCommandLine has "dscl"
 | where ProcessCommandLine has "-authonly"
 | project Timestamp, DeviceId, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine

Telegram Bot API exfiltration detection

Search for network connections to Telegram Bot API endpoints, used by this campaign to exfiltrate stolen credentials.

DeviceNetworkEvents
 | where Timestamp > ago(30d)
 | where RemoteUrl has "api.telegram.org" and RemoteUrl has "/bot"
 | project Timestamp, DeviceId, DeviceName, RemoteUrl, RemoteIP, RemotePort, InitiatingProcessFileName, InitiatingProcessCommandLine

Reflective code loading using NSCreateObjectFileImageFromMemory

Search for evidence of reflective Mach-O loading, the technique used by the icloudz backdoor to execute code in memory.

DeviceEvents
 | where Timestamp > ago(30d)
 | where ActionType has "NSCreateObjectFileImageFromMemory"
     or AdditionalFields has "NSCreateObjectFileImageFromMemory"
 | project Timestamp, DeviceId, DeviceName, ActionType, FileName, FolderPath, InitiatingProcessFileName, AdditionalFields

Suspicious caffeinate and sleep prevention activity

Search for caffeinate process stop-and-restart patterns used by the services and icloudz backdoors to prevent the system from sleeping during backdoor operations.

DeviceProcessEvents
 | where Timestamp > ago(30d)
 | where ProcessCommandLine has "caffeinate"
 | where InitiatingProcessCommandLine has_any ("icloudz", "services", "chromes.updaters", "zsh -i")
 | project Timestamp, DeviceId, DeviceName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine

Detect known malicious file hashes

Search for the specific malicious file hashes associated with this Sapphire Sleet campaign across file events.

let malicious_hashes = dynamic([
     "2075fd1a1362d188290910a8c55cf30c11ed5955c04af410c481410f538da419",
     "05e1761b535537287e7b72d103a29c4453742725600f59a34a4831eafc0b8e53",
     "5fbbca2d72840feb86b6ef8a1abb4fe2f225d84228a714391673be2719c73ac7",
     "5e581f22f56883ee13358f73fabab00fcf9313a053210eb12ac18e66098346e5",
     "95e893e7cdde19d7d16ff5a5074d0b369abd31c1a30962656133caa8153e8d63",
     "8fd5b8db10458ace7e4ed335eb0c66527e1928ad87a3c688595804f72b205e8c",
     "a05400000843fbad6b28d2b76fc201c3d415a72d88d8dc548fafd8bae073c640"
 ]);
 DeviceFileEvents
 | where Timestamp > ago(30d)
 | where SHA256 in (malicious_hashes)
 | project Timestamp, DeviceId, DeviceName, FileName, FolderPath, SHA256, ActionType, InitiatingProcessFileName, InitiatingProcessCommandLine

Data staging and exfiltration activity

Search for ZIP archive creation in /tmp/ directories followed by curl uploads matching the staging-and-exfiltration pattern used for browser data, crypto wallets, Telegram sessions, SSH keys, and Apple Notes.

DeviceProcessEvents
 | where Timestamp > ago(30d)
 | where (ProcessCommandLine has "zip" and ProcessCommandLine has "/tmp/")
     or (ProcessCommandLine has "curl" and ProcessCommandLine has_any ("tapp_", "ext_", "ldg_", "exds_", "hs_", "nt_", "lg_"))
 | project Timestamp, DeviceId, DeviceName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine

Script Editor launching suspicious child processes

Search for Script Editor (the default handler for .scpt files) spawning curl, osascript, or shell commands—the initial execution vector in this campaign.

DeviceProcessEvents
 | where Timestamp > ago(30d)
 | where InitiatingProcessFileName == "Script Editor" or InitiatingProcessCommandLine has "Script Editor"
 | where FileName has_any ("curl", "osascript", "sh", "bash", "zsh")
 | project Timestamp, DeviceId, DeviceName, FileName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine

Microsoft Sentinel

Microsoft Sentinel customers can use the TI Mapping analytics (a series of analytics all prefixed with ‘TI map’) to automatically match the malicious domain indicators mentioned in this blog post with data in their workspace. If the TI Map analytics are not currently deployed, customers can install the Threat Intelligence solution from the Microsoft Sentinel Content Hub to have the analytics rule deployed in their Sentinel workspace.

Detect network indicators of compromise

The following query checks for connections to the Sapphire Sleet C2 domains and IP addresses across network session data:

let lookback = 30d;
 let ioc_domains = dynamic(["uw04webzoom.us", "uw05webzoom.us", "uw03webzoom.us", "ur01webzoom.us", "uv01webzoom.us", "uv03webzoom.us", "uv04webzoom.us", "ux06webzoom.us", "check02id.com"]);
 let ioc_ips = dynamic(["188.227.196.252", "83.136.208.246", "83.136.209.22", "83.136.208.48", "83.136.210.180", "104.145.210.107"]);
 DeviceNetworkEvents
 | where TimeGenerated > ago(lookback)
 | where RemoteUrl has_any (ioc_domains) or RemoteIP in (ioc_ips)
 | summarize EventCount=count() by DeviceName, RemoteUrl, RemoteIP, RemotePort, InitiatingProcessFileName

Detect file hash indicators of compromise

The following query searches for the known malicious file hashes associated with this campaign across file, process, and security event data:

let selectedTimestamp = datetime(2026-01-01T00:00:00.0000000Z);
 let FileSHA256 = dynamic([
     "2075fd1a1362d188290910a8c55cf30c11ed5955c04af410c481410f538da419",
     "05e1761b535537287e7b72d103a29c4453742725600f59a34a4831eafc0b8e53",
     "5fbbca2d72840feb86b6ef8a1abb4fe2f225d84228a714391673be2719c73ac7",
     "5e581f22f56883ee13358f73fabab00fcf9313a053210eb12ac18e66098346e5",
     "95e893e7cdde19d7d16ff5a5074d0b369abd31c1a30962656133caa8153e8d63",
     "8fd5b8db10458ace7e4ed335eb0c66527e1928ad87a3c688595804f72b205e8c",
     "a05400000843fbad6b28d2b76fc201c3d415a72d88d8dc548fafd8bae073c640"
 ]);
 search in (AlertEvidence, DeviceEvents, DeviceFileEvents, DeviceImageLoadEvents, DeviceProcessEvents, DeviceNetworkEvents, SecurityEvent, ThreatIntelligenceIndicator)
 TimeGenerated between ((selectedTimestamp - 1m) .. (selectedTimestamp + 90d))
 and (SHA256 in (FileSHA256) or InitiatingProcessSHA256 in (FileSHA256))

Detect Microsoft Defender Antivirus detections related to Sapphire Sleet

The following query searches for Defender Antivirus alerts for the specific malware families used in this campaign and joins with device information for enriched context:

let SapphireSleet_threats = dynamic([
     "Trojan:MacOS/NukeSped.D",
     "Trojan:MacOS/PassStealer.D",
     "Trojan:MacOS/SuspMalScript.C",
     "Trojan:MacOS/SuspInfostealExec.C"
 ]);
 SecurityAlert
 | where ProviderName == "MDATP"
 | extend ThreatName = tostring(parse_json(ExtendedProperties).ThreatName)
 | extend ThreatFamilyName = tostring(parse_json(ExtendedProperties).ThreatFamilyName)
 | where ThreatName in~ (SapphireSleet_threats) or ThreatFamilyName in~ (SapphireSleet_threats)
 | extend CompromisedEntity = tolower(CompromisedEntity)
 | join kind=inner (
     DeviceInfo
     | extend DeviceName = tolower(DeviceName)
 ) on $left.CompromisedEntity == $right.DeviceName
 | summarize arg_max(TimeGenerated, *) by DisplayName, ThreatName, ThreatFamilyName, PublicIP, AlertSeverity, Description, tostring(LoggedOnUsers), DeviceId, TenantId, CompromisedEntity, ProductName, Entities
 | extend HostName = tostring(split(CompromisedEntity, ".")[0]), DomainIndex = toint(indexof(CompromisedEntity, '.'))
 | extend HostNameDomain = iff(DomainIndex != -1, substring(CompromisedEntity, DomainIndex + 1), CompromisedEntity)
 | project-away DomainIndex
 | project TimeGenerated, DisplayName, ThreatName, ThreatFamilyName, PublicIP, AlertSeverity, Description, LoggedOnUsers, DeviceId, TenantId, CompromisedEntity, ProductName, Entities, HostName, HostNameDomain

Indicators of compromise

Malicious file hashes

FileSHA-256
/Users/<user>/Downloads/Zoom SDK Update.scpt2075fd1a1362d188290910a8c55cf30c11ed5955c04af410c481410f538da419
/Users/<user>/com.apple.cli05e1761b535537287e7b72d103a29c4453742725600f59a34a4831eafc0b8e53
/Users/<user>/Library/Services/services
 services / icloudz
5fbbca2d72840feb86b6ef8a1abb4fe2f225d84228a714391673be2719c73ac7
com.google.chromes.updaters5e581f22f56883ee13358f73fabab00fcf9313a053210eb12ac18e66098346e5
com.google.webkit.service.plist95e893e7cdde19d7d16ff5a5074d0b369abd31c1a30962656133caa8153e8d63
/private/tmp/SystemUpdate/systemupdate.app/Contents/MacOS/Mac Password Popup8fd5b8db10458ace7e4ed335eb0c66527e1928ad87a3c688595804f72b205e8c
/private/tmp/SoftwareUpdate/softwareupdate.app/Contents/MacOS/Mac Password Popupa05400000843fbad6b28d2b76fc201c3d415a72d88d8dc548fafd8bae073c640

Domains and IP addresses

DomainIP addressPortPurpose
uw04webzoom[.]us188.227.196[.]252443Payload staging
check02id[.]com83.136.210[.]1805202chromes.updaters
 83.136.208[.]2466783com.apple.cli invocated with IP and port
 and beacon
 83.136.209[.]228444Downloadsservices backdoor
 83.136.208[.]48443services invoked with IP and port
 104.145.210[.]1076783Exfiltration

Acknowledgments

Existing blogs with similar behavior tracked:

Learn more

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The post Dissecting Sapphire Sleet’s macOS intrusion from lure to compromise appeared first on Microsoft Security Blog.

  • ✇Security Boulevard
  • Claude Mythos and the Cybersecurity Risk That Was Already Here Jacob Krell
    On March 26, Anthropic confirmed the existence of Claude Mythos, an unreleased AI model described internally as "a step change" in capabilities, after a data leak exposed approximately 3,000 unpublished assets in a publicly searchable, unencrypted data store (Fortune, March 26, 2026). The leak was not a sophisticated intrusion. A toggle switch in Anthropic's content management system was left in the wrong position, setting digital assets to public by default (Fortune, March 26, 2026). Amon
     

Claude Mythos and the Cybersecurity Risk That Was Already Here

27 de Março de 2026, 16:15

On March 26, Anthropic confirmed the existence of Claude Mythos, an unreleased AI model described internally as "a step change" in capabilities, after a data leak exposed approximately 3,000 unpublished assets in a publicly searchable, unencrypted data store (Fortune, March 26, 2026). The leak was not a sophisticated intrusion. A toggle switch in Anthropic's content management system was left in the wrong position, setting digital assets to public by default (Fortune, March 26, 2026). Among the exposed materials were internal assessments describing Mythos as posing "unprecedented cybersecurity risks" and being "far ahead of any other AI model in cyber capabilities" (World Today News, March 2026).

The post Claude Mythos and the Cybersecurity Risk That Was Already Here appeared first on Security Boulevard.

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