The following analytic identifies a suspicious process command line fetching the environment variables with a non-shell parent process. This technique was seen in qakbot malware where it fetches the environment variable in the target or compromised host. This TTP detection is a good pivot of possible malicious behavior since the command line is executed by a common non-shell process like cmd.exe , powershell.exe and many more. This can also be a good sign that the parent process has a malicious code injected to it to execute this command.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-10-27
- Author: Teoderick Contreras, Splunk
- ID: 048839e4-1eaa-43ff-8a22-86d17f6fcc13
Kill Chain Phase
- CIS 10
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.process = "*cmd /c set" OR Processes.process = "*cmd.exe /c set" AND NOT (Processes.parent_process_name = "cmd.exe" OR Processes.parent_process_name = "powershell*" OR Processes.parent_process_name="pwsh.exe" OR Processes.parent_process_name = "explorer.exe") by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.original_file_name | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_command_shell_fetch_env_variables_filter`
The SPL above uses the following Macros:
windows_command_shell_fetch_env_variables_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
The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the
Processes node of the
Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
Known False Positives
shell process that are not included in this search may cause False positive. Filter is needed.
Associated Analytic Story
|56.0||80||70||non-shell parent process has a child process $process_name$ with a commandline $process$ to fetch env variables in $dest$|
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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