Suspicious modification of a user account SPN to enable Kerberoast attack

title: Suspicious modification of a user account SPN to enable Kerberoast attack
description: Detects scenarios where an attacker update the Service Principal Name (SPN) of a user account in order to enable Kerberoast attack and crack its password.
requirements: auditing SACL ("Write all properties") must be placed on the OU to monitor using the Active Directory console (https://www.manageengine.com/products/active-directory-audit/active-directory-auditing-configuration-guide-configure-object-level-auditing-manually.html).
references:
- https://github.com/mdecrevoisier/EVTX-to-MITRE-Attack/tree/master/TA0003-Persistence/T1098.xxx-Account%20manipulation
- https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-5136
- https://github.com/S1ckB0y1337/Active-Directory-Exploitation-Cheat-Sheet#force-set-spn
- https://docs.microsoft.com/en-us/troubleshoot/windows-server/windows-security/use-audit-active-directory-objects-track-events
tags:
- attack.persistence
- attack.t1098
author: mdecrevoisier
status: experimental
logsource:
  product: windows
  service: security
detection:
  selection:
    EventID: 5136 # ID 4738 doesn't report any changes about SPN changes
    AttributeLDAPDisplayName: servicePrincipalName
    ObjectClass: user
    OperationType: '%%14674' # Value is added
  filter:
    AttributeValue: '-'
  condition: selection and not filter
falsepositives:
- Rare administrator modifications on user objects
level: high