Detectionhightest
Wusa.EXE Executed By Parent Process Located In Suspicious Location
Detects execution of the "wusa.exe" (Windows Update Standalone Installer) utility by a parent process that is located in a suspicious location. Attackers could instantiate an instance of "wusa.exe" in order to bypass User Account Control (UAC). They can duplicate the access token from "wusa.exe" to gain elevated privileges.
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Launch
X__Junior (Nextron Systems)Created Sun Nov 26Updated Thu Aug 15ef64fc9c-a45e-43cc-8fd8-7d75d73b4c99windows
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation
Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.
Detection Logic
Detection Logic4 selectors
detection:
selection_img:
Image|endswith: '\wusa.exe'
selection_paths_1:
ParentImage|contains:
# Note: Add additional suspicious locations to increase coverage
- ':\Perflogs\'
- ':\Users\Public\'
- ':\Windows\Temp\'
- '\Appdata\Local\Temp\'
- '\Temporary Internet'
selection_paths_2:
- ParentImage|contains|all:
- ':\Users\'
- '\Favorites\'
- ParentImage|contains|all:
- ':\Users\'
- '\Favourites\'
- ParentImage|contains|all:
- ':\Users\'
- '\Contacts\'
- ParentImage|contains|all:
- ':\Users\'
- '\Pictures\'
filter_main_msu:
# Note: We exclude MSU extension files. A better approach is to baseline installation of updates in your env to avoid false negatives.
CommandLine|contains: '.msu'
condition: selection_img and 1 of selection_paths_* and not 1 of filter_main_*False Positives
Unknown
False positive likelihood has not been assessed. Additional context may be needed during triage.
References
MITRE ATT&CK
Tactics
Rule Metadata
Rule ID
ef64fc9c-a45e-43cc-8fd8-7d75d73b4c99
Status
test
Level
high
Type
Detection
Created
Sun Nov 26
Modified
Thu Aug 15
Path
rules/windows/process_creation/proc_creation_win_wusa_susp_parent_execution.yml
Raw Tags
attack.execution