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PASSEDvendor / sophos_central_edr_quarantine_storm
Sophos Central EDR Quarantine Storm
A Sophos Central Intercept X update causes the EDR engine to quarantine a critical Windows system DLL across all managed endpoints, rendering 300 workstations unable to run key business applications.
Pattern
UNKNOWN
Severity
CRITICAL
Confidence
95%
Remediation
Remote Hands
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | UNKNOWN | UNKNOWN | |
| Severity Assessment | CRITICAL | CRITICAL | |
| Incident Correlation | Yes | 20 linked | |
| Cascade Escalation | N/A | No | |
| Remediation | — | Remote Hands — Corax contacts on-site support via call, email, or API |
Scenario Conditions
Sophos Central managing 300 Windows endpoints. Intercept X signature update flags msvcr140.dll as malicious. Auto-quarantine removes the DLL. 300 workstations affected. All C++ runtime applications broken.
Injected Error Messages (2)
sophos Central EDR quarantine storm — Intercept X deep learning model update (version 2026.3.28.4) falsely identified msvcr140.dll as 'ML/PE-A' (machine learning generic detection), sophos auto-quarantine removed the DLL from 300 managed Windows endpoints, all applications using Visual C++ 2015-2022 Redistributable crashing with 'DLL not found' errors
sophos Central mass quarantine event affecting 300 endpoints — sophos Intercept X removed critical system DLL msvcr140.dll, applications affected: ERP client, email, CRM, reporting tools, sophos Central admin console showing 300 'threat cleaned' events for false positive detection 'ML/PE-A', manual DLL restoration required on all affected machines, sophos Central auto-quarantine policy causing widespread business disruption
Neural Engine Root Cause Analysis
Sophos Central EDR experienced a false positive detection storm caused by a faulty deep learning model update (version 2026.3.28.4) that incorrectly classified msvcr140.dll as malware 'ML/PE-A'. This critical Windows system DLL was automatically quarantined across 300 managed endpoints, causing widespread application crashes for any software dependent on Visual C++ 2015-2022 Redistributable. The cascading failures across multiple systems indicate this is a vendor-side AI model issue affecting the entire managed fleet, not an infrastructure problem with the Sophos Central dashboard itself.
Remediation Plan
1. Immediately contact Sophos support to report the false positive detection and request emergency model rollback. 2. Access Sophos Central admin console and create quarantine exclusion rule for msvcr140.dll across all managed endpoints. 3. Restore quarantined msvcr140.dll files from quarantine on all affected endpoints (can be done via Sophos Central bulk action). 4. Monitor endpoint status and verify application functionality recovery. 5. Hold Sophos EDR updates until vendor confirms model fix and provides updated detection engine. 6. Document incident and review change management processes for third-party security tool updates.
Tested: 2026-03-30Monitors: 2 | Incidents: 2Test ID: cmnck7i6p07byobqeczvd78nc