Potential Shadow Credentials added to AD Object

Elastic Stack Serverless Security

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.

Rule type: query

Rule indices:

• winlogbeat-*
• logs-system.*

Severity: high

Risk score: 73

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References:

• https://posts.specterops.io/shadow-credentials-abusing-key-trust-account-mapping-for-takeover-8ee1a53566ab
• https://www.thehacker.recipes/ad/movement/kerberos/shadow-credentials
• https://github.com/OTRF/Set-AuditRule

Tags:

• Elastic
• Host
• Windows
• Threat Detection
• Credential Access
• Active Directory

Version: 4

Rule authors:

• Elastic

Rule license: Elastic License v2

event.action:"Directory Service Changes" and event.code:"5136" and winlog.event_data.AttributeLDAPDisplayName:"msDS-KeyCredentialLink"

Framework: MITRE ATT&CKTM

• Tactic:

  • Name: Credential Access
  • ID: TA0006
  • Reference URL: https://attack.mitre.org/tactics/TA0006/

• Technique:

  • Name: Modify Authentication Process
  • ID: T1556
  • Reference URL: https://attack.mitre.org/techniques/T1556/