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Description

This analytic looks for suspicious command-lines that can be possibly used to modify user profile files to automatically execute scripts/executables by shell upon reboot of the machine. This technique is commonly abused by adversaries, malware and red teamers as persistence mechanism to the targeted or compromised host. This Anomaly detection is a good indicator that someone wants to run code after reboot which can be done also by the administrator or network operator for automation purposes.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-12-20
  • Author: Teoderick Contreras, Splunk
  • ID: 9c94732a-61af-11ec-91e3-acde48001122

ATT&CK

ID Technique Tactic
T1546.004 Unix Shell Configuration Modification Privilege Escalation, Persistence
T1546 Event Triggered Execution Privilege Escalation, Persistence

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process = "*echo*" AND Processes.process IN("*~/.bashrc", "*~/.bash_profile", "*/etc/profile", "~/.bash_login", "*~/.profile", "~/.bash_logout") 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_possible_append_command_to_profile_config_file_filter`

Associated Analytic Story

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.

Required field

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

Kill Chain Phase

  • Privilege Escalation

Known False Positives

Administrator or network operator can use this commandline for automation purposes. Please update the filter macros to remove false positives.

RBA

Risk Score Impact Confidence Message
49.0 70 70 a commandline $process$ that may modify profile files in $dest$

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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