huntrule

Suspicious AS-REP Roasting LDAP Search Filter for DONT_REQ_PREAUTH Accounts

PremiumReviewedSigma · High · v1
Product
windows
Service
security
Author
HuntRule
Published
2026-05-28
Updated
2026-08-28
AnalysisDetection

ATT&CK techniques

Cred Access → Discovery

  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 Directory Service search event 1644 carrying an LDAP filter that uses the bitwise OID to select accounts with the DONT_REQUIRE_PREAUTH flag set, matching Impacket GetNPUsers enumeration for AS-REP roasting. Adversaries query these accounts to request roastable tickets crackable offline. This precise bitwise filter is rarely produced by legitimate directory tooling.

Reporting behind it

Related detections9 linkedT1087.002 — drag to rearrange
Suspicious Active Directory Export via Csvde via Process Creation (via process_creation)
Suspicious AdFind Domain User Reconnaissance Output
Suspicious Active Directory Reconnaissance Output via ADRecon CSV (via file_event)
Suspicious Domain Computer Enumeration via Net Group Command
Suspicious Active Directory Enumeration via AdsiSearcher
Suspicious ADFind Active Directory Reconnaissance Execution
Malicious IcedID AdFind Active Directory Reconnaissance via Command Line
Suspicious ADFind Active Directory Enumeration (via process_creation)
Suspicious SOAPHound Style LDAP Query with SDflags and all_with_list via security
Suspicious AS-REP Roasting LDAP Search Filter for DONT_REQ_PREAUTH Accounts
Pivot detection · T1087.002 · 9 related

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