Potential Reverse Shell

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This detection rule identifies suspicious network traffic patterns associated with TCP reverse shell activity. This activity consists of a parent-child relationship where a network event is followed by the creation of a shell process. An attacker may establish a Linux TCP reverse shell to gain remote access to a target system.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Domain: Endpoint
  • OS: Linux
  • Use Case: Threat Detection
  • Tactic: Execution

Version: 2

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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sequence by host.id with maxspan=1s
[ network where host.os.type == "linux" and event.type == "start" and event.action == "connection_attempted" and
  process.name : ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish", "socat") and
  destination.ip != null and destination.ip != "127.0.0.1" and destination.ip != "::1" ] by process.entity_id
[ process where host.os.type == "linux" and event.type == "start" and event.action : ("exec", "fork") and
  process.name : ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish") and
  process.parent.name : ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish", "socat") ] by process.parent.entity_id

Framework: MITRE ATT&CKTM