Spoolsv Suspicious Loaded Modules
This search is to detect suspicious loading of dll in specific path relative to printnightmare exploitation. In this search we try to detect the loaded modules made by spoolsv.exe after the exploitation.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2021-07-01
- Author: Mauricio Velazco, Michael Haag, Teoderick Contreras, Splunk
- ID: a5e451f8-da81-11eb-b245-acde48001122
Kill Chain Phase
|CVE-2021-34527||Windows Print Spooler Remote Code Execution Vulnerability||9.0|
1 2 3 4 5 6 `sysmon` EventCode=7 Image ="*\\spoolsv.exe" ImageLoaded="*\\Windows\\System32\\spool\\drivers\\x64\\*" ImageLoaded = "*.dll" | stats dc(ImageLoaded) as countImgloaded values(ImageLoaded) as ImgLoaded count min(_time) as firstTime max(_time) as lastTime by Image Computer ProcessId EventCode | where countImgloaded >= 3 | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `spoolsv_suspicious_loaded_modules_filter`
The SPL above uses the following Macros:
spoolsv_suspicious_loaded_modules_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
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
Associated Analytic Story
|72.0||80||90||$Image$ with process id $process_id$ has loaded a driver from $ImageLoaded$ on endpoint $Computer$. This behavior is suspicious and related to PrintNightmare.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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source | version: 2