Detection rules › Sigma
PetitPotam Suspicious Kerberos TGT Request
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.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Credential Access | T1187 Forced Authentication |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Security-Auditing | 4768 | A Kerberos authentication ticket (TGT) was requested. |
Stages and Predicates
Stage 1: selection
CertThumbprint|contains: '*'
TargetUserName|endswith: '$'
Stage 2: not 1 of filter_*
or:
CertThumbprint: ''
IpAddress: '::1'
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.
| Field | Kind | Values |
|---|---|---|
CertThumbprint | match |
|
IpAddress | eq |
|
TargetUserName | ends_with |
|