Name:Windows UAC Bypass Suspicious Child Process id:453a6b0f-b0ea-48fa-9cf4-20537ffdd22c version:7 date:2025-02-10 author:Steven Dick status:production type:TTP Description:The following analytic detects when an executable known for User Account Control (UAC) bypass exploitation spawns a child process in a user-controlled location or a command shell executable (e.g., cmd.exe, powershell.exe). This detection leverages Sysmon EventID 1 data, focusing on high or system integrity level processes with specific parent-child process relationships. This activity is significant as it may indicate an attacker has successfully used a UAC bypass exploit to escalate privileges. If confirmed malicious, this could allow the attacker to execute arbitrary commands with elevated privileges, potentially compromising the entire system. Data_source:
-Sysmon EventID 1
-Windows Event Log Security 4688
-CrowdStrike ProcessRollup2
search:| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_integrity_level IN ("high","system") AND Processes.parent_process_name IN (`uacbypass_process_name`) AND (Processes.process_name IN ("cmd.exe","powershell.exe","pwsh.exe","wscript","cscript.exe","bash.exe","werfault.exe") OR Processes.process IN ("*\\\\*","*\\Users\\*","*\\ProgramData\\*","*\\Temp\\*")) by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product | `drop_dm_object_name(Processes)` | where parent_process_name != process_name | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_uac_bypass_suspicious_child_process_filter`
how_to_implement:Target environment must ingest sysmon data, specifically Event ID 1 with process integrity level data. known_false_positives:Including Werfault.exe may cause some unintended false positives related to normal application faulting, but is used in a number of UAC bypass techniques. References: -https://attack.mitre.org/techniques/T1548/002/ -https://atomicredteam.io/defense-evasion/T1548.002/ -https://hadess.io/user-account-control-uncontrol-mastering-the-art-of-bypassing-windows-uac/ -https://enigma0x3.net/2016/08/15/fileless-uac-bypass-using-eventvwr-exe-and-registry-hijacking/ drilldown_searches: name:'View the detection results for - "$dest$" and "$user$"' search:'%original_detection_search% | search dest = "$dest$" user = "$user$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$" and "$user$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user$") 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)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'Windows Defense Evasion Tactics' - 'Living Off The Land' asset_type:Endpoint mitre_attack_id: - 'T1548.002' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' security_domain:endpoint
