This search is to detect a suspicious loaded unsigned dll by MMC.exe application. This technique is commonly seen in attacker that tries to bypassed UAC feature or gain privilege escalation. This is done by modifying some CLSID registry that will trigger the mmc.exe to load the dll path
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2021-07-12
- Author: Teoderick Contreras, Splunk
- ID: 7f04349c-e30d-11eb-bc7f-acde48001122
Kill Chain Phase
1 2 3 4 5 `sysmon` EventCode=7 ImageLoaded = "*.dll" Image = "*\\mmc.exe" Signed=false Company != "Microsoft Corporation" | stats count min(_time) as firstTime max(_time) as lastTime by Image ImageLoaded Signed ProcessId OriginalFileName Computer EventCode Company | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `uac_bypass_mmc_load_unsigned_dll_filter`
The SPL above uses the following Macros:
Note that uac_bypass_mmc_load_unsigned_dll_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
How To Implement
To successfully implement this search, you need to be ingesting logs with the process name and imageloaded executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
Known False Positives
unknown. all of the dll loaded by mmc.exe is microsoft signed dll.
Associated Analytic story
|63.0||70||90||Suspicious unsigned $ImageLoaded$ loaded by $Image$ on endpoint $Computer$ with EventCode $EventCode$|
source | version: 1