Detection rules › Sigma
Bypass UAC Using SilentCleanup Task
Detects the setting of the environement variable "windir" to a non default value. Attackers often abuse this variable in order to trigger a UAC bypass via the "SilentCleanup" task. The SilentCleanup task located in %windir%\system32\cleanmgr.exe is an auto-elevated task that can be abused to elevate any file with administrator privileges without prompting UAC.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Privilege Escalation | T1548.002 Abuse Elevation Control Mechanism: Bypass User Account Control |
| Defense Evasion | T1548.002 Abuse Elevation Control Mechanism: Bypass User Account Control |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 13 | RegistryEvent (Value Set) |
Stages and Predicates
Stage 1: selection
TargetObject|endswith: '\Environment\windir'
Stage 2: not 1 of filter_main_default
Details: '%SystemRoot%'
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 |
|---|---|---|
Details | eq |
|
TargetObject | ends_with |
|