ID | Technique | Tactic |
---|---|---|
T1021.004 | SSH | Lateral Movement |
Detection: Linux SSH Remote Services Script Execute
Description
The following analytic detects the use of SSH to move laterally and execute a script or file on a remote host. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific SSH command-line parameters and URLs. This activity is significant as it may indicate an attacker attempting to execute remote commands or scripts, potentially leading to unauthorized access or control over additional systems. If confirmed malicious, this could result in lateral movement, privilege escalation, or the execution of malicious payloads, compromising the security of the network.
Search
1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=ssh Processes.process IN ("*oStrictHostKeyChecking*", "*oConnectTimeout*", "*oBatchMode*") AND Processes.process IN ("*http:*","*https:*") by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
3| `drop_dm_object_name(Processes)`
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| `linux_ssh_remote_services_script_execute_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
Sysmon for Linux EventID 1 | Linux | 'sysmon:linux' |
'Syslog:Linux-Sysmon/Operational' |
N/A |
Macros Used
Name | Value |
---|---|
security_content_ctime | convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$) |
linux_ssh_remote_services_script_execute_filter | search * |
linux_ssh_remote_services_script_execute_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
Default Configuration
This detection is configured by default in Splunk Enterprise Security to run with the following settings:
Setting | Value |
---|---|
Disabled | true |
Cron Schedule | 0 * * * * |
Earliest Time | -70m@m |
Latest Time | -10m@m |
Schedule Window | auto |
Creates Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
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
This is not a common command to be executed. Filter as needed.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
An instance of $process_name$ was identified on endpoint $dest$ by user $user$ attempting to move laterally and download a file. | 56 | 80 | 70 |
References
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | Syslog:Linux-Sysmon/Operational |
sysmon:linux |
Integration | ✅ Passing | Dataset | Syslog:Linux-Sysmon/Operational |
sysmon:linux |
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: GitHub | Version: 3