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Deprecated - Potential Reverse Shell via Suspicious Parent Process

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Deprecated - Potential Reverse Shell via Suspicious Parent Process

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This detection rule detects the creation of a shell through a suspicious parent child relationship. Any reverse shells spawned by the specified utilities that use a forked process to initialize the connection attempt will be captured through this rule. Attackers may spawn reverse shells to establish persistence onto 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:

https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/Methodology%20and%20Resources/Reverse%20Shell%20Cheatsheet.md

Tags:

Domain: Endpoint
OS: Linux
Use Case: Threat Detection
Tactic: Execution
Data Source: Elastic Defend

Version: 6

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

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This rule was deprecated due to its addition to the umbrella `Potential Reverse Shell via Suspicious Child Process` (76e4d92b-61c1-4a95-ab61-5fd94179a1ee) rule.

Rule query

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sequence by host.id, process.parent.entity_id with maxspan=1s
[ process where host.os.type == "linux" and event.type == "start" and event.action == "fork" and (
  (process.name : "python*" and process.args == "-c" and not process.args == "/usr/bin/supervisord") or
  (process.name : "php*" and process.args == "-r") or
  (process.name : "perl" and process.args == "-e") or
  (process.name : "ruby" and process.args in ("-e", "-rsocket")) or
  (process.name : "lua*" and process.args == "-e") or
  (process.name : "openssl" and process.args : "-connect") or
  (process.name : ("nc", "ncat", "netcat") and process.args_count >= 3 and not process.args == "-z") or
  (process.name : "telnet" and process.args_count >= 3) or
  (process.name : "awk")) and
  process.parent.name : ("python*", "php*", "perl", "ruby", "lua*", "openssl", "nc", "netcat", "ncat", "telnet", "awk") ]
[ network where host.os.type == "linux" and event.type == "start" and event.action in ("connection_attempted", "connection_accepted") and
  process.name : ("python*", "php*", "perl", "ruby", "lua*", "openssl", "nc", "netcat", "ncat", "telnet", "awk") and
  destination.ip != null and destination.ip != "127.0.0.1" and destination.ip != "::1" ]

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/
Sub-technique:
- Name: Unix Shell
- ID: T1059.004
- Reference URL: https://attack.mitre.org/techniques/T1059/004/
Tactic:
- Name: Command and Control
- ID: TA0011
- Reference URL: https://attack.mitre.org/tactics/TA0011/
Technique:
- Name: Application Layer Protocol
- ID: T1071
- Reference URL: https://attack.mitre.org/techniques/T1071/

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