The following analytic identifies the use of Plink being utilized to proxy egress or laterally in an organization. The analytic is limited to specific Plink options on the command-line, including -R -L and -D which will have the remote and local IP address or port and -l for a username. Modify the options as seen fit for your organization.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-09-15
- Author: Michael Haag, Splunk
- ID: 8aac5e1e-0fab-4437-af0b-c6e60af23eed
Kill Chain Phase
- Command & Control
- CIS 3
- CIS 5
- CIS 16
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_name=plink.exe OR Processes.original_file_name=Plink Processes.process IN ("*-R *", "*-L *", "*-D *", "*-l *") 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_protocol_tunneling_with_plink_filter`
The SPL above uses the following Macros:
windows_protocol_tunneling_with_plink_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
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 may be present if the organization allows for SSH tunneling outbound or internally. Filter as needed.
Associated Analytic Story
|56.0||70||80||An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ attempting to tunnel to a remote destination.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 1