Potential Reverse Shell Activity via Terminal

Elastic Stack Serverless Security

Identifies the execution of a shell process with suspicious arguments which may be indicative of reverse shell activity.

Rule type: eql

Rule indices:

• auditbeat-*
• logs-endpoint.events.*

Severity: high

Risk score: 73

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References:

• https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/Methodology%20and%20Resources/Reverse%20Shell%20Cheatsheet.md
• https://github.com/WangYihang/Reverse-Shell-Manager
• https://www.netsparker.com/blog/web-security/understanding-reverse-shells/

Tags:

• Elastic
• Host
• Linux
• macOS
• Threat Detection
• Execution

Version: 2

Rule authors:

• Elastic

Rule license: Elastic License v2

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define event.ingested and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate event.ingested to @timestamp for this rule to work.

process where event.type in ("start", "process_started") and
  process.name in ("sh", "bash", "zsh", "dash", "zmodload") and
  process.args:("*/dev/tcp/*", "*/dev/udp/*", "zsh/net/tcp", "zsh/net/udp")

Framework: MITRE ATT&CKTM

• 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/