huntrule

Windows Registry Winlogon AllowMultipleTSSessions Enabled

Alerts on enabling Winlogon AllowMultipleTSSessions (DWORD 0x00000001), allowing concurrent RDP sessions.

FreeReviewedSigma · Medium · v1
Product
windows
Category
registry_set
Author
Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-09-09
Updated
2026-07-30
AnalysisDetection

ATT&CK techniques

Persistence → 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 when the Winlogon registry setting AllowMultipleTSSessions is set to DWORD 0x00000001. Enabling this setting allows multiple simultaneous Remote Desktop sessions, which can help an attacker connect to an RDP session without interrupting existing user sessions. It relies on registry set telemetry that captures TargetObject and the written Details value for the specific Winlogon path.

Reporting behind it

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Malicious WDigest UseLogonCredential Enabled for Cleartext Credential Theft (via registry_set)
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Windows Registry Winlogon AllowMultipleTSSessions Enabled
Pivot detection · T1112 · 9 related

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