Techniques
Sample rules
Unusual Number of Remote Endpoint Authentication Events
- source: splunk
- technicques:
- T1078
Description
The following hunting analytic leverages Event ID 4624, An account was successfully logged on, to identify an unusual number of remote authentication attempts coming from one source. An endpoint authenticating to a large number of remote 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 high number of authentication events.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=4624 Logon_Type=3 Account_Name!="*$"
| eval Source_Account = mvindex(Account_Name, 1)
| bucket span=2m _time
| stats dc(ComputerName) AS unique_targets values(ComputerName) as target_hosts by _time, Source_Network_Address, Source_Account
| eventstats avg(unique_targets) as comp_avg , stdev(unique_targets) as comp_std by Source_Network_Address, Source_Account
| eval upperBound=(comp_avg+comp_std*3)
| eval isOutlier=if(unique_targets >10 and unique_targets >= upperBound, 1, 0)
| `unusual_number_of_remote_endpoint_authentication_events_filter`