[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fP-F3nAld0mUBCBhhmvyO-3cpzsq6Rpzi6B3s9Ju5QRw":3},{"lesson":4},{"id":5,"slug":6,"article_id":7,"title":8,"body":9,"prevention":10,"framework_refs":11,"framework_notes":24,"status":25,"created_at":26,"published_at":27,"article":28,"tags":32,"podcasts":51,"controls":58},"e49cf00d-3fd3-47f5-8376-d9ca150e9cd4","acr-stealer-exploits-clickfix-social-engineering-to-harvest-browser-tokens-and-m365-data","fe44e7bc-a05b-41b1-b746-d29f46234551","ACR Stealer Exploits ClickFix Social Engineering to Harvest Browser Tokens and M365 Data","ACR Stealer succeeds primarily because users are socially engineered into voluntarily executing malicious commands via the Windows Run box — a technique that bypasses many traditional security controls by weaponizing human behavior. The use of both fileless (memory-resident) and disk-based delivery chains makes detection significantly harder, allowing stolen browser session tokens and Microsoft 365 documents to be exfiltrated before defenses can respond. Compromised authentication tokens are especially dangerous because they can grant attackers persistent access to cloud resources like OneDrive and SharePoint without requiring credentials. This attack highlights that even well-configured environments are vulnerable when users lack the awareness to recognize social engineering lures. The escalation in campaign activity from April through June 2026 underscores the urgency of addressing the human element alongside technical controls.","**Immediate actions:**\n- Deploy application control policies (e.g., AppLocker or WDAC) to block unauthorized execution of commands pasted into the Windows Run box or PowerShell.\n- Enforce short-lived session token lifetimes and require re-authentication for sensitive Microsoft 365 operations to limit the value of stolen tokens.\n- Enable Microsoft Defender's tamper protection and memory-based threat detection to catch fileless malware execution in real time.\n\n**User awareness & training:**\n- Train all employees to recognize ClickFix-style lures — specifically any prompt instructing them to copy\u002Fpaste commands into Windows Run, PowerShell, or a terminal.\n- Conduct simulated social engineering exercises targeting Run-box and clipboard-based attack techniques to build user muscle memory against these lures.\n\n**Long-term improvements:**\n- Implement continuous identity threat detection, including anomalous token usage alerts, across all Microsoft 365 and cloud services.\n- Apply Zero Trust principles by enforcing conditional access policies that validate device health, location, and risk score before granting access to SharePoint and OneDrive.\n- Establish a Data Loss Prevention (DLP) policy to detect and block exfiltration of PDFs and Office documents through unauthorized channels.",[12,13,14,15,16,17,18,19,20,21,22,23],"CIS Control 2: Inventory and Control of Software Assets","CIS Control 14: Security Awareness and Skills Training","CIS Control 16: Application Software Security","NIST SP 800-53 AT-2: Security Awareness Training","NIST SP 800-53 AC-12: Session Termination","NIST SP 800-53 SI-3: Malicious Code Protection","NIST SP 800-53 IA-11: Re-Authentication","MITRE ATT&CK T1059: Command and Scripting Interpreter","MITRE ATT&CK T1539: Steal Web Session Cookie","MITRE ATT&CK T1566: Phishing \u002F Social Engineering","GDPR Article 32: Security of Processing (data exfiltration risk)","NIST Zero Trust Architecture SP 800-207",{},"published","2026-07-17T12:21:45.53768+00:00","2026-07-17T12:21:45.38+00:00",{"id":7,"url":29,"slug":30,"title":31},"https:\u002F\u002Fthehackernews.com\u002F2026\u002F07\u002Facr-stealer-uses-clickfix-lures-to.html","acr-stealer-uses-clickfix-lures-to-steal-browser-tokens-and-microsoft-365-files-d7cd26","ACR Stealer Uses ClickFix Lures to Steal Browser Tokens and Microsoft 365 Files",[33,39,45],{"id":34,"name":35,"slug":36,"description":37,"color":38},"1ec88fde-2d0f-4ed8-932a-33f5ccc0fdc7","Access Control","access-control","Excessive privileges, missing MFA, weak auth","#f97316",{"id":40,"name":41,"slug":42,"description":43,"color":44},"7261eb8f-acd4-4d93-a489-7fdd652ec0ea","Security Awareness","security-awareness","Phishing, social engineering, human error","#22c55e",{"id":46,"name":47,"slug":48,"description":49,"color":50},"c8b843a5-d5a7-41d1-8d3b-cabded09d2ef","Data Protection","data-protection","Unencrypted data, missing DLP, poor classification","#3b82f6",[52],{"id":53,"date":54,"edition":55,"title":56,"audio_url":57},"b84f4fbc-88d1-4fc5-a9b8-52781d663292","2026-07-17","afternoon","ThreatNoir Afternoon Brief — July 17","https:\u002F\u002Fcdn.threatnoir.com\u002Fpodcasts\u002F2026-07-17\u002Fthreatnoir-afternoon-brief-2026-07-17.mp3",[59,63,67],{"slug":60,"name":61,"problem":62},"endpoint-detection-response","Endpoint detection and response (EDR and XDR)","Malware and hands-on-keyboard attackers on laptops and servers get spotted and stopped.",{"slug":64,"name":65,"problem":66},"data-loss-prevention","Data loss prevention (DLP)","Sensitive data cannot quietly leave by email, upload, USB stick or AI tool.",{"slug":68,"name":69,"problem":70},"security-awareness-training","Security awareness training and phishing simulation","People recognise and report attacks instead of falling for them."]