Detection rules › Sigma

UAC Bypass Using Windows Media Player - Process

Severity
high
Author
Christian Burkard (Nextron Systems)
Source
upstream

Detects the pattern of UAC Bypass using Windows Media Player osksupport.dll (UACMe 32)

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1548.002 Abuse Elevation Control Mechanism: Bypass User Account Control
Defense EvasionT1548.002 Abuse Elevation Control Mechanism: Bypass User Account Control

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation

Stages and Predicates

Stage 1: 1 of selection_img_1

Image: 'C:\Program Files\Windows Media Player\osk.exe'

Stage 2: 1 of selection_img_2

Image: 'C:\Windows\System32\cmd.exe'
ParentCommandLine: '"C:\Windows\system32\mmc.exe" "C:\Windows\system32\eventvwr.msc" /s'

Stage 3: selection_integrity

IntegrityLevel: [High, S-1-16-12288, S-1-16-16384, System]

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.

FieldKindValues
Imageeq
  • C:\Program Files\Windows Media Player\osk.exe
  • C:\Windows\System32\cmd.exe corpus 3 (sigma 3)
IntegrityLeveleq
  • High corpus 16 (sigma 16)
  • S-1-16-12288 corpus 16 (sigma 16)
  • S-1-16-16384 corpus 21 (sigma 21)
  • System corpus 21 (sigma 21)
ParentCommandLineeq
  • "C:\Windows\system32\mmc.exe" "C:\Windows\system32\eventvwr.msc" /s