Windows Indirect Command Execution Via forfiles
Description
The following analytic detects programs that have been started by forfiles.exe. According to Microsoft, the 'The forfiles command lets you run a command on or pass arguments to multiple files'. While this tool can be used to start legitimate programs, usually within the context of a batch script, it has been observed being used to evade protections on command line execution.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-04-05
- Author: Eric McGinnis, Splunk
- ID: 1fdf31c9-ff4d-4c48-b799-0e8666e08787
Annotations
Kill Chain Phase
- Exploitation
NIST
- DE.AE
CIS20
- CIS 8
- CIS 10
CVE
Search
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| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process="*forfiles* /c *" by Processes.dest Processes.user Processes.parent_process Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.process_path
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_indirect_command_execution_via_forfiles_filter`
Macros
The SPL above uses the following Macros:
windows_indirect_command_execution_via_forfiles_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Supported Add-on (TA)
List of Splunk Add-on’s tested to work with the analytic.
Required fields
List of fields required to use this analytic.
- _time
- Processes.dest
- Processes.user
- Processes.dest
- Processes.user
- Processes.parent_process
- Processes.parent_process_name
- Processes.process_name
- Processes.process
- Processes.process_id
- Processes.parent_process_id
- Processes.process_path
How To Implement
To successfully implement this search, you need to be ingesting logs with the full process path in the process field of CIM's Process data model. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. Tune and filter known instances where forfiles.exe may be used.
Known False Positives
Some legacy applications may be run using pcalua.exe. Similarly, forfiles.exe may be used in legitimate batch scripts. Filter these results as needed.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
25.0 | 50 | 50 | The Program Compatability Assistant (pcalua.exe) launched the process $process_name$ |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
Reference
- https://twitter.com/KyleHanslovan/status/912659279806640128
- https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/forfiles
Test Dataset
Replay any dataset to Splunk Enterprise by using our replay.py
tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
source | version: 1