Detection rules › Splunk
Unusual Number of Computer Service Tickets Requested
The following analytic identifies an unusual number of computer service ticket requests from a single source, leveraging Event ID 4769, "A Kerberos service ticket was requested." It uses statistical analysis, including standard deviation and the 3-sigma rule, to detect anomalies in service ticket requests. This activity is significant as it may indicate malicious behavior such as lateral movement, malware staging, or reconnaissance. If confirmed malicious, an attacker could gain unauthorized access to multiple endpoints, facilitating further compromise and potential data exfiltration.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | T1078 Valid Accounts |
| Persistence | T1078 Valid Accounts |
| Privilege Escalation | T1078 Valid Accounts |
| Defense Evasion | T1078 Valid Accounts |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Security-Auditing | 4769 | A Kerberos service ticket was requested. |
Stages and Predicates
Stage 1: search
search Account_Name!="*$*" EventCode=4769 Service_Name="*$"
Stage 2: bucket
bucket span=2m _time
Stage 3: stats
stats dc(Service_Name) AS unique_targets, … AS host_targets BY _time, Client_Address, Account_Name
Stage 4: eventstats
eventstats avg(unique_targets) AS comp_avg BY Client_Address, Account_Name
Stage 5: eval
eval ... using (comp_avg, comp_std)
Stage 6: eval
eval ... using (unique_targets, upperBound)
Stage 7: search
search `macro`
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 |
|---|---|---|
Account_Name | ne |
|
EventCode | eq |
|
Service_Name | eq |
|
Neighbors
Broader alternatives (more inclusive than this rule)
These rules match a superset of what this rule catches. They cover the same events plus more. Use them if you want wider coverage and can absorb more false positives.
- Suspicious Kerberos Service Ticket Request (drops 2 filters this rule applies)