Possible SonicWall Credential Testing via userLogin Endpoint

PremiumReviewedSigma · Medium · v1
Category
webserver
Author
HuntRule
Published
2026-07-09
Updated
2026-08-28

ATT&CK techniques

Initial Access → Cred Access
  1. Recon

  2. Resource Dev

  3. Execution

  4. Persistence

  5. Priv Esc

  6. Defense Evasion

  7. Cred Access

  8. Discovery

  9. Lateral Movement

  10. Collection

  11. C2

  12. Exfiltration

  13. Impact

What it detects

This rule detects HTTP POST requests to the SonicWall /cgi-bin/userLogin endpoint, the interface used by NetExtender and web login for credential submission. In the observed campaign this endpoint is hit through commercial proxy infrastructure to test credentials against internet-facing SonicWall firewalls. A high rate of such POST requests indicates brute-force or credential-stuffing activity against the SSL-VPN login surface.

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