CAR-2021-01-008: Disable UAC
Threat actors often, after compromising a machine, try to disable User Access Control (UAC) to escalate privileges. This is often done by changing the registry key for system policies using “reg.exe”, a legitimate tool provided by Microsoft for modifying the registry via command prompt or scripts. This action interferes with UAC and may enable a threat actor to escalate privileges on the compromised system, thereby allowing further exploitation of the system.
ATT&CK Detections
Technique | Subtechnique(s) | Tactic(s) | Level of Coverage |
---|---|---|---|
Abuse Elevation Control Mechanism | Bypass User Account Control | Privilege Escalation | Medium |
D3FEND Techniques
ID | Name |
---|---|
D3-PSA | Process Spawn Analysis |
Data Model References
Object | Action | Field |
---|---|---|
process | create | image_path |
process | create | command_line |
Implementations
Detect disabling of UAC via reg.exe (Splunk, Sysmon native)
This query looks for the specific use of reg.exe in correlation to commands aimed at disabling UAC.
sourcetype = __your_sysmon_index__ ParentImage = "C:\\Windows\\System32\\cmd.exe" | where like(CommandLine,"reg.exe%HKLM\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System%REG_DWORD /d 0%")
Detect disabling of UAC via reg.exe (Pseudocode, Sysmon native)
This query looks for the specific use of reg.exe in correlation to commands aimed at disabling UAC.
processes = search Process:Create
cmd_processes = filter processes where (
(parent_image = "C:\\Windows\\System32\\cmd.exe") AND (command_line = "reg.exe%HKLM\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\System%REG_DWORD /d 0%")
)