Techniques
Sample rules
Windows Defender MpClient.dll Loaded by Non-Defender Process
- source: splunk
- technicques:
Description
The following analytic detects mpclient.dll, the Windows Defender client API library, being loaded by a process that is not part of the Windows Defender platform. mpclient.dll exposes the API surface used to drive on-demand Defender scans (IOAV, MpScan). In the ShieldBreak exploit, the attacker binary loads mpclient.dll directly and calls its scan APIs against an object-manager path in order to trigger a Defender scan against attacker-controlled content as part of a race condition targeting Defender’s placeholder-hydration behavior. If confirmed malicious, this activity indicates an attempt to weaponize Windows Defender’s own scanning pipeline for local privilege escalation.
Detection logic
| tstats `security_content_summariesonly`
count min(_time) as firstTime
max(_time) as lastTime
from datamodel=Endpoint.Processes where
Processes.loaded_file="mpclient.dll"
NOT Processes.user IN ("* SERVICE", "SYSTEM")
NOT Processes.process_path="*\MpCmdRun.exe"
Processes.process_path IN (
"*:\\AppData\\Local\\Temp\\*",
"*:\\Perflogs\\*",
"*:\\ProgramData\\*",
"*:\\Temp\\*",
"*:\\Users\\*",
"*:\\Windows\\Tasks\\*"
)
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.loaded_file 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)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_defender_mpclient_dll_loaded_by_non_defender_process_filter`