Detection rules › Elastic

Potential Shadow Credentials added to AD Object

Author
Elastic
Source
upstream

Identify the modification of the msDS-KeyCredentialLink attribute in an Active Directory Computer or User Object. Attackers can abuse control over the object and create a key pair, append to raw public key in the attribute, and obtain persistent and stealthy access to the target user or computer object.

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1098 Account Manipulation, T1556 Modify Authentication Process
Privilege EscalationT1098 Account Manipulation
Defense EvasionT1556 Modify Authentication Process
Credential AccessT1556 Modify Authentication Process

Event coverage

ProviderEvent IDTitle
Security-Auditing5136A directory service object was modified.

Stages and Predicates

Stage 1: kql:query

not winlog.event_data.SubjectUserName:"MSOL_*" and winlog.event_data.AttributeLDAPDisplayName:"msDS-KeyCredentialLink" and winlog.event_data.AttributeValue:"B\\:828*"

Exclusions

Top-level NOT(...) conjuncts — predicates this rule actively suppresses.

StageFieldKindExcluded values
1userstarts_withMSOL_

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
winlog.event_data.AttributeLDAPDisplayNameeq
  • msDS-KeyCredentialLink corpus 2 (sigma 1, elastic 1)
winlog.event_data.AttributeValuewildcard
  • B\:828*

Neighbors

Broader alternatives (more inclusive than this rule)

These rules match a superset of what this rule catches. They cover the same events plus more. Use them if you want wider coverage and can absorb more false positives.