Detection rules › Sigma

Kerberoasting Activity - Initial Query

Severity
medium
Author
@kostastsale
Source
upstream

This rule will collect the data needed to start looking into possible kerberoasting activity. Further analysis or computation within the query is needed focusing on requests from one specific host/IP towards multiple service names within a time period of 5 seconds. You can then set a threshold for the number of requests and time between the requests to turn this into an alert.

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1558.003 Steal or Forge Kerberos Tickets: Kerberoasting

Event coverage

ProviderEvent IDTitle
Security-Auditing4769A Kerberos service ticket was requested.

Stages and Predicates

Stage 1: selection

Status: 0x0
TicketEncryptionType: 0x17

Stage 2: not 1 of filter_main_*

or:
ServiceName|endswith: '$'
ServiceName|endswith: krbtgt
TargetUserName|contains: '$@'

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
ServiceNameends_with
  • $ corpus 2 (sigma 2)
  • krbtgt
Statuseq
  • 0x0
TargetUserNamematch
  • $@
TicketEncryptionTypeeq
  • 0x17 corpus 7 (splunk 4, sigma 3)