Techniques
Sample rules
Unusual Number of Computer Service Tickets Requested
- source: splunk
- technicques:
- T1078
Description
The following hunting analytic leverages Event ID 4769, A Kerberos service ticket was requested, to identify an unusual number of computer service ticket requests from one source. When a domain joined endpoint connects to a remote endpoint, it first will request a Kerberos Ticket with the computer name as the Service Name. An endpoint requesting a large number of computer service tickets for different endpoints could represent malicious behavior like lateral movement, malware staging, reconnaissance, etc. The detection calculates the standard deviation for each host and leverages the 3-sigma statistical rule to identify an unusual number of service requests. To customize this analytic, users can try different combinations of the bucket span time, the calculation of the upperBound field as well as the Outlier calculation. This logic can be used for real time security monitoring as well as threat hunting exercises.
Detection logic
`wineventlog_security` EventCode=4769 Service_Name="*$" Account_Name!="*$*"
| bucket span=2m _time
| stats dc(Service_Name) AS unique_targets values(Service_Name) as host_targets by _time, Client_Address, Account_Name
| eventstats avg(unique_targets) as comp_avg , stdev(unique_targets) as comp_std by Client_Address, Account_Name
| eval upperBound=(comp_avg+comp_std*3)
| eval isOutlier=if(unique_targets >10 and unique_targets >= upperBound, 1, 0)
| `unusual_number_of_computer_service_tickets_requested_filter`