huntrule

Windows RPCSS svchost (-k RPCSS) Process Spawn Anomaly (Potential CVE-2022-26809)

Alerts on svchost.exe running RPCSS spawning anomalous child processes indicative of potential RPC abuse.

FreeReviewedSigma · High · v5
Product
windows
Category
process_creation
Author
Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-04-13
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Initial Access → Execution

  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 Windows process creation events where svchost.exe running the RPCSS instance (ParentCommandLine contains "-k RPCSS") spawns a subprocess. This matters because RPC service anomalies can indicate attempted exploitation paths that result in unexpected child processes from a core Windows service host. It relies on process creation telemetry including the parent image and parent command line used to identify the RPCSS context.

Reporting behind it

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Windows RPCSS svchost (-k RPCSS) Process Spawn Anomaly (Potential CVE-2022-26809)
Pivot detection · T1190 · 9 related

Changelog

v5
  1. v5
    Candidate ingested via manual entry.2026-07-31
  2. v4
    Candidate ingested via manual entry.2026-07-31
  3. v3
    Candidate ingested via manual entry.2026-07-31
  4. v2
    Candidate ingested via manual entry.2026-07-31
  5. v1
    No changelog recorded for this version.2026-07-30

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