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Description

This analytic looks for possible installing a linux kernel module using modprobe utility function. This event can detect a installation of rootkit or malicious kernel module to gain elevated privileges to their malicious code and bypassed detections. This Anomaly detection is a good indicator that someone installing kernel module in a linux host either admin or adversaries. filter is needed in this scenario

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-12-22
  • Author: Teoderick Contreras, Splunk
  • ID: 387b278a-6326-11ec-aa2c-acde48001122

Annotations

ATT&CK
ID Technique Tactic
T1547.006 Kernel Modules and Extensions Persistence, Privilege Escalation
T1547 Boot or Logon Autostart Execution Persistence, Privilege Escalation
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE
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 IN("kmod", "sudo") AND Processes.process = *modprobe* by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.process_guid 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `linux_install_kernel_module_using_modprobe_utility_filter`

Macros

The SPL above uses the following Macros:

:information_source: linux_install_kernel_module_using_modprobe_utility_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

  • _time
  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_id

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you can use the Add-on for Linux Sysmon from Splunkbase.

Known False Positives

Administrator or network operator can execute this command. Please update the filter macros to remove false positives.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
64.0 80 80 A commandline $process$ that may install kernel module on $dest$

:information_source: 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

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

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