Name:Windows Admin Password Changed by Non-Admin id:6d4c4d88-cd60-43a1-8c70-c74a9614f724 version:2 date:None author:Raven Tait, Splunk status:production type:TTP Description:The following analytic detects when a unprivileged user changes an Admin accounts password. This is a common artifact of successful exploitation of the BlueHammer Windows Defender privilege escalation. The attacker's process momentarily changes the passwords of high-value local accounts including the built-in Administrator to spawn an authenticated shell session, then immediately reverts the passwords to avoid detection. This uses EventID 4723 to log this activity. Data_source:
| rex field=TargetSid "-(?<target_rid>\d+)$" | rex field=SubjectUserSid "-(?<subject_rid>\d+)$"
| where tonumber(target_rid)=500 OR tonumber(target_rid) IN (512,513,518,519,520) | where tonumber(subject_rid) >= 1000 | where subject_rid != target_rid
| stats count min(_time) as firstTime max(_time) as lastTime
by dest TargetSid EventCode SubjectUserSid src_user TargetUserName
how_to_implement:The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process. known_false_positives:Some IT support tools or automated scripts may change administrator passwords during maintenance. Verify changes against authorized administrative activities to reduce false alerts. References: -https://github.com/Nightmare-Eclipse/BlueHammer drilldown_searches: earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View the detection results for - "$dest$"' search:'%original_detection_search% | search dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' analytic_story:['Windows Privilege Escalation', 'BlueHammer']
