Potential Reverse Shell Activity via Terminal

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 (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

Elastic
Host
Linux
macOS
Threat Detection
Execution

Version: 5

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

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## Setup

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.

Rule query

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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*") and

  /* noisy FPs */
  not (process.parent.name : "timeout" and process.executable : "/var/lib/docker/overlay*") and
  not process.command_line : ("*/dev/tcp/sirh_db/*", "*/dev/tcp/remoteiot.com/*", "*dev/tcp/elk.stag.one/*", "*dev/tcp/kafka/*", "*/dev/tcp/$0/$1*", "*/dev/tcp/127.*", "*/dev/udp/127.*", "*/dev/tcp/localhost/*") and
  not process.parent.command_line : "runc init"

Framework: MITRE ATT&CK^TM

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/

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