huntrule

Windows cmd.exe Command-Line Anomaly: Missing Spaces Around /c /k /r

Flags cmd.exe invocations with suspicious missing spaces around /c, /k, or /r based on process creation CommandLine patterns.

FreeReviewedSigma · High · v2
Product
windows
Category
process_creation
Author
Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-08-23
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

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 cmd.exe is executed with a /c, /k, or /r flag but the command line is missing required surrounding spaces (e.g., 'cmd.exe/c' or 'cmd.exe /c' patterns not matching the expected spacing). Attackers may leverage inconsistent spacing patterns to evade simplistic parsing, hide intent, or introduce execution quirks during command construction. The detection relies on process_creation telemetry and string matching within the captured CommandLine field.

Reporting behind it

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Suspicious PowerShell Download of Disguised Payload to ProgramData
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Windows cmd.exe Command-Line Anomaly: Missing Spaces Around /c /k /r
Pivot detection · T1059.001 · 9 related

Changelog

v2
  1. v2
    Candidate ingested via manual entry.2026-07-31
  2. 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.