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Detection rules › Sigma

Host constrained delegation settings changed for potential abuse (Rubeus) - Kerberos only

Status
experimental
Severity
high
Log source
product windows, service security
Author
mdecrevoisier
Source
github.com/mdecrevoisier/SIGMA-detection-rules

Detects scenarios where an attacker modifies host delegation settings for privilege escalation.

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1098 Account Manipulation

Event coverage

ProviderEventTitle
Security-AuditingEvent ID 4742A computer account was changed.

Rule body yaml

title: Host constrained delegation settings changed for potential abuse (Rubeus) - Kerberos only
description: Detects scenarios where an attacker modifies host delegation settings for privilege escalation.
references:
- https://github.com/mdecrevoisier/EVTX-to-MITRE-Attack/tree/master/TA0003-Persistence/T1098.xxx-Account%20manipulation
- https://dirkjanm.io/krbrelayx-unconstrained-delegation-abuse-toolkit/
- https://www.alsid.com/crb_article/kerberos-delegation/
- https://www.harmj0y.net/blog/activedirectory/s4u2pwnage/
- https://shenaniganslabs.io/2019/01/28/Wagging-the-Dog.html
- https://www.ired.team/offensive-security-experiments/active-directory-kerberos-abuse/abusing-kerberos-constrained-delegation
- https://www.guidepointsecurity.com/delegating-like-a-boss-abusing-kerberos-delegation-in-active-directory/
- https://stealthbits.com/blog/what-is-kerberos-delegation-an-overview-of-kerberos-delegation/
- https://posts.specterops.io/hunting-in-active-directory-unconstrained-delegation-forests-trusts-71f2b33688e1
- https://www.thehacker.recipes/ad/movement/kerberos/delegations#talk
tags:
- attack.persistence
- attack.t1098
author: mdecrevoisier
status: experimental
logsource:
  product: windows
  service: security
detection:
  selection: # Delegation to specified service, Kerberos only
    EventID: 4742
    UserAccountControl: '-'  # Avoid duplicate with with "constrained delegation to any protocol"
  filter:
    AllowedToDelegateTo: '-' # Can be: "cifs/srv01 cifs/srv02.demo.lan dcom/dc03..."
  condition: selection and not filter
falsepositives:
- Rare administrator modifying host delegation settings
level: high

Stages and Predicates

Stage 0: condition

selection and not filter

Stage 1: selection

selection:
  EventID: 4742
  UserAccountControl: '-'

Stage 2: not filter

filter:
  AllowedToDelegateTo: '-'

Exclusions

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

FieldKindExcluded values
AllowedToDelegateToeq-

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
UserAccountControleq
  • -