The following detection identifies Microsoft Word spawning
cmd.exe. Typically, this is not common behavior and not default with winword.exe. Winword.exe will generally be found in the following path
C:\Program Files\Microsoft Office\root\Office16 (version will vary). Cmd.exe spawning from winword.exe is common for a spearphishing attachment and is actively used. Albeit, the command-line will indicate what is being executed. During triage, review parallel processes and identify any files that may have been written. It is possible that COM is utilized to trampoline the child process to
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint- Datasource: Splunk Add-on for Sysmon
- Last Updated: 2021-04-22
- Author: Michael Haag, Splunk
- ID: 6fcbaedc-a37b-11eb-956b-acde48001122
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=winword.exe `process_cmd` by Processes.dest Processes.user Processes.parent_process Processes.original_file_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `winword_spawning_cmd_filter`
The SPL above uses the following Macros:
Note that winword_spawning_cmd_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, but if any are present, filter as needed.
Associated Analytic story
|70.0||70||100||$parent_process_name$ on $dest$ by $user$ launched command: $process_name$ which is very common in spearphishing attacks.|
source | version: 2