---
title: Linux Restricted Shell Breakout via the SSH command
description: Identifies Linux binary SSH abuse to break out from restricted environments by spawning an interactive system shell. The SSH protocol is a network protocol...
url: https://www.elastic.co/elastic/docs-builder/docs/3167/reference/security/prebuilt-rules/rules/_deprecated/execution_ssh_binary
products:
  - Elastic Security
---

# Linux Restricted Shell Breakout via the SSH command
<warning>
  This rule has been deprecated as of 2022/05/09.
</warning>

Identifies Linux binary SSH abuse to break out from restricted environments by spawning an interactive system shell. The
SSH protocol is a network protocol that gives users, particularly system administrators, a secure way to access a
computer over a network. The activity of spawning shell is not a standard use of this binary for a user or system
administrator. It indicates a potentially 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/ssh/](https://gtfobins.github.io/gtfobins/ssh/)](https://gtfobins.github.io/gtfobins/ssh/)

**Tags**:
- Elastic
- Host
- Linux
- Threat Detection
- Execution
- GTFOBins

**Version**: 100
**Rule authors**:
- Elastic

**Rule license**: Elastic License v2

## Rule Query

```eql
process where event.type == "start" and process.name : ("bash", "sh", "dash") and
  process.parent.name == "ssh" and process.parent.args == "-o" and
  process.parent.args in ("ProxyCommand=;sh 0<&2 1>&2", "ProxyCommand=;bash 0<&2 1>&2", "ProxyCommand=;dash 0<&2 1>&2", "ProxyCommand=;/bin/sh 0<&2 1>&2", "ProxyCommand=;/bin/bash 0<&2 1>&2", "ProxyCommand=;/bin/dash 0<&2 1>&2")
```

**Framework:** MITRE ATT&CK
- Tactic:
  - Name: Execution
- Id: TA0002
- Reference URL: [[https://attack.mitre.org/tactics/TA0002/](https://attack.mitre.org/tactics/TA0002/)](https://attack.mitre.org/tactics/TA0002/)
- Technique:
  - Name: Command and Scripting Interpreter
- Id: T1059
- Reference URL: [[https://attack.mitre.org/techniques/T1059/](https://attack.mitre.org/techniques/T1059/)](https://attack.mitre.org/techniques/T1059/)
- Sub Technique:
  - Name: Unix Shell
- Id: T1059.004
- Reference URL: [[https://attack.mitre.org/techniques/T1059/004/](https://attack.mitre.org/techniques/T1059/004/)](https://attack.mitre.org/techniques/T1059/004/)