huntrule

Suspicious Data Exfiltration to Anonymous File Sharing Services (via dns_query)

PremiumReviewedSigma · Medium · v1
Product
windows
Category
dns_query
Author
HuntRule
Published
2026-06-22
Updated
2026-08-28
AnalysisDetection

ATT&CK techniques

Exfiltration

  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 detects DNS lookups for the anonfiles and bayfiles anonymous file sharing services, which the Cyclops stealer uses to upload harvested victim data over web services. Exfiltration to anonymous upload endpoints lets the attacker collect stolen credentials and documents while evading corporate data controls.

Reporting behind it

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Suspicious Data Exfiltration to Anonymous File Sharing Services (via dns_query)
Pivot detection · T1567.002 · 9 related

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