KRBTGT Delegation Backdoor

Identifies the modification of the msDS-AllowedToDelegateTo attribute to KRBTGT. Attackers can use this technique to maintain persistence to the domain by having the ability to request tickets for the KRBTGT service.

Rule type: eql

Rule indices:

winlogbeat-*
logs-system.*
logs-windows.*

Severity: high

Risk score: 73

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

Domain: Endpoint
OS: Windows
Use Case: Threat Detection
Tactic: Persistence
Use Case: Active Directory Monitoring
Data Source: Active Directory
Data Source: System

Version: 208

Rule authors:

Elastic

Rule license: Elastic License v2

Setup

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Setup

The Audit User Account Management logging policy must be configured for (Success, Failure). Steps to implement the logging policy with Advanced Audit Configuration:

Computer Configuration >
Policies >
Windows Settings >
Security Settings >
Advanced Audit Policies Configuration >
Audit Policies >
Account Management >
Audit User Account Management (Success,Failure)

Rule query

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iam where event.action == "modified-user-account" and event.code == "4738" and
  winlog.event_data.AllowedToDelegateTo : "*krbtgt*"

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
Technique:
- Name: Account Manipulation
- ID: T1098
- Reference URL: https://attack.mitre.org/techniques/T1098/
Tactic:
- Name: Credential Access
- ID: TA0006
- Reference URL: https://attack.mitre.org/tactics/TA0006/
Technique:
- Name: Steal or Forge Kerberos Tickets
- ID: T1558
- Reference URL: https://attack.mitre.org/techniques/T1558/

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