huntrule

Windows Sysmon DNS Query to .onion or Tor Gateway Domains

Alerts when Windows Sysmon DNS queries target .onion or Tor gateway/proxy-related domain suffixes.

FreeReviewedSigma · High · v2
Product
windows
Category
dns_query
Author
frack113 (SigmaHQ), DRL 1.1
Published
2022-02-20
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

C2

  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 DNS queries where the queried name ends with .onion, .hiddenservice.net, .onion.* TLDs, Tor gateway subdomains (s1–s5.tor-gateways.de), or tor2web/torlink domains. Attackers may use these domains to reach Tor-hidden services or related routing/proxy infrastructure, making DNS lookups a valuable early signal for command-and-control and evasion. It relies on Windows Sysmon DNS query telemetry, specifically the QueryName field ending with the listed patterns.

Reporting behind it

Related detections2 linkedT1090.003 — drag to rearrange
Windows Process Execution of Tor or Tor Browser (tor.exe / Firefox-based)
Windows DNS Client Query for .onion and Tor-related Domains
Windows Sysmon DNS Query to .onion or Tor Gateway Domains
Pivot detection · T1090.003 · 2 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.