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Windows: vsls-agent.exe Executed With --agentExtensionPath Suspicious Library Load

Flags vsls-agent.exe launched with --agentExtensionPath, suggesting a potentially suspicious external extension/library load.

FreeReviewedSigma · Medium · v1
Product
windows
Category
process_creation
Author
bohops (SigmaHQ), DRL 1.1
Published
2022-10-30
Updated
2026-07-30
AnalysisDetection

ATT&CK techniques

Defense Evasion

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule flags process creations where Microsoft Visual Studio vsls-agent.exe is launched with the --agentExtensionPath parameter, indicating an attempted external extension/library load. Attackers may use this execution pattern to load untrusted code or extend agent behavior while masquerading as a legitimate binary. The detection relies on process creation telemetry, specifically the executed image path ending in vsls-agent.exe and the command-line arguments containing --agentExtensionPath, with a reduction for cases referencing Microsoft.VisualStudio.LiveShare.Agent.

Reporting behind it

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Windows: vsls-agent.exe Executed With --agentExtensionPath Suspicious Library Load
Pivot detection · T1218 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.