The following analytic identifies the use of Microsoft Remote Assistance, msra.exe, spawning PowerShell.exe or cmd.exe as a child process. Msra.exe by default has no command-line arguments and typically spawns itself. It will generate a network connection to the remote system that is connected. This behavior is indicative of another process injected into msra.exe. Review the parent process or cross process events to identify source.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-02-07
- Author: Michael Haag, Splunk
- ID: ced50492-8849-11ec-9f68-acde48001122
|T1055||Process Injection||Defense Evasion, Privilege Escalation|
Kill Chain Phase
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name=msra.exe `windows_shells` by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_remote_assistance_spawning_process_filter`
The SPL above uses the following Macros:
Note that windows_remote_assistance_spawning_process_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 information on process that include the name of the process responsible for the changes from your endpoints into the
Endpoint datamodel in the
Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
Known False Positives
False positives should be limited, filter as needed. Add additional shells as needed.
Associated Analytic story
|80.0||80||100||An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$, generating behavior not common with msra.exe.|
source | version: 1