Linux Restricted Shell Breakout via the vi command

Identifies Linux binary find abuse to break out from restricted environments by spawning an interactive system shell. The vi/vim editor is the standard text editor in Linux distributions, and the activity of spawning a shell is not a standard use of this binary by a user or system administrator. This could potentially indicate a malicious actor attempting to improve the capabilities or stability of their access.

Rule type: eql
Rule indices:

• logs-endpoint.events.*

Rule Severity: medium
Risk Score: 47
Runs every:
Searches indices from: now-9m
Maximum alerts per execution: 100
References:

• https://gtfobins.github.io/gtfobins/vi/

Tags:

• Elastic
• Host
• Linux
• Threat Detection
• Execution
• GTFOBins

Version: 100
Rule authors:

• Elastic

Rule license: Elastic License v2

process where event.type == "start" and process.parent.name in ("vi", "vim") and process.parent.args == "-c" and process.parent.args in (":!/bin/bash", ":!/bin/sh", ":!bash", ":!sh") and process.name in ("bash", "sh")
		

Framework: MITRE ATT&CK

• Tactic:

  • Name: Execution
  • Id: TA0002
  • Reference URL: https://attack.mitre.org/tactics/TA0002/

• Technique:

  • Name: Command and Scripting Interpreter
  • Id: T1059
  • Reference URL: https://attack.mitre.org/techniques/T1059/

• Sub Technique:

  • Name: Unix Shell
  • Id: T1059.004
  • Reference URL: https://attack.mitre.org/techniques/T1059/004/