Suspicious Machine Account Replication - DcSync Indicator
Detects suspicious Active Directory Replication Service (ADRS) requests originating from a machine account (SubjectUserName ending in '$') rather than a legitimate Domain Controller. Under normal operation, only…
Description
Detects suspicious Active Directory Replication Service (ADRS) requests originating from a machine account (SubjectUserName ending in '$') rather than a legitimate Domain Controller. Under normal operation, only Domain Controllers initiate replication requests carrying the DS-Replication-Get-Changes-All right. If a threat actor obtains valid machine account credentials — for example by abusing certificate-based authentication (PKINIT) to impersonate a DC after exploiting a CA vulnerability such as CVE-2026-54121 (Certighost), where a temporary machine account is created to request a DC certificate and then used to perform DCSync — they can dump all domain credential material including the krbtgt hash.
Detection logic
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| blog.blacklanternsecurity.com/p/detecting-dcsync?s=r | Only this detection cites it |
| gist.github.com/gentilkiwi/dcc132457408cf11ad2061340dcb53c2 | 3from 2 sources |
| github.com/aniqfakhrul/CVE-2026-54121 | 2from 2 sources |
| learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-4662 | 2 |
| twitter.com/gentilkiwi/status/1003236624925413376 | 2 |
From the source
- At source
- Open at source
- Upstream identifier
- 611eab06-a145-4dfa-a295-3ccc5c20f59a
- Tagged by the source as
- attack.credential-accessattack.s0002cve.2026-54121
Licence
- Published under
- Detection Rule License 1.1Read the licence
- Attribution
- Required
Authorship
- Published
- Aug 26, 2026
- Version
- 1