title: PetitPotam Suspicious Kerberos TGT Request
id: 6a53d871-682d-40b6-83e0-b7c1a6c4e3a5
description: Detect suspicious Kerberos TGT requests. Once an attacer obtains a computer
  certificate by abusing Active Directory Certificate Services in combination with
  PetitPotam, the next step would be to leverage the certificate for malicious purposes.
  One way of doing this is to request a Kerberos Ticket Granting Ticket using a tool
  like Rubeus. This request will generate a 4768 event with some unusual fields depending
  on the environment. This analytic will require tuning, we recommend filtering Account_Name
  to the Domain Controller computer accounts.
status: experimental
author: Mauricio Velazco, Michael Haag
date: 2021/09/02
modified: 2021/09/07
references:
    - https://github.com/topotam/PetitPotam
    - https://isc.sans.edu/forums/diary/Active+Directory+Certificate+Services+ADCS+PKI+domain+admin+vulnerability/27668/
    - https://github.com/splunk/security_content/blob/develop/detections/endpoint/petitpotam_suspicious_kerberos_tgt_request.yml
tags:
    - attack.credential_access
    - attack.t1187
logsource:
    product: windows
    service: security
    definition: 'The advanced audit policy setting "Account Logon > Kerberos Authentication Service" must be configured for Success/Failure'
detection:
    selection:
        EventID: 4768
        TargetUserName|endswith: '$'
        CertThumbprint: '*'
    filter_local:
        IpAddress: '::1'
    filter_thumbprint:
        CertThumbprint: ''
    condition: selection and not 1 of filter_*
falsepositives:
    - False positives are possible if the environment is using certificates for authentication. We recommend filtering Account_Name to the Domain Controller computer accounts.
level: high
