Detect Renamed PSExec
Description
The following analytic identifies renamed instances of PsExec.exe
being utilized on an endpoint. Most instances, it is highly probable to capture Psexec.exe
or other SysInternal utility usage with the command-line argument of -accepteula
. During triage, validate this is the legitimate version of PsExec
by reviewing the PE metadata. In addition, review parallel processes for further suspicious behavior.
- Type: Hunting
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-04-07
- Author: Michael Haag, Splunk
- ID: 683e6196-b8e8-11eb-9a79-acde48001122
Annotations
ATT&CK
Kill Chain Phase
- Installation
NIST
- DE.AE
CIS20
- 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.process_name!=psexec.exe OR Processes.process_name!=psexec64.exe) AND Processes.original_file_name=psexec.c 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)`
| `detect_renamed_psexec_filter`
Macros
The SPL above uses the following Macros:
detect_renamed_psexec_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Required fields
List of fields required to use this analytic.
- _time
- Processes.dest
- Processes.user
- Processes.parent_process_name
- Processes.parent_process
- Processes.original_file_name
- Processes.process_name
- Processes.process
- Processes.process_id
- Processes.parent_process_path
- Processes.process_path
- Processes.parent_process_id
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
Limited false positives should be present. It is possible some third party applications may use older versions of PsExec, filter as needed.
Associated Analytic Story
- SamSam Ransomware
- DHS Report TA18-074A
- HAFNIUM Group
- DarkSide Ransomware
- Active Directory Lateral Movement
- CISA AA22-320A
- Sandworm Tools
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
27.0 | 30 | 90 | The following $process_name$ has been identified as renamed, spawning from $parent_process_name$ on $dest$ by $user$. |
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://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1569.002/T1569.002.yaml
- https://redcanary.com/blog/threat-hunting-psexec-lateral-movement/
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: 4