Tampering of Bash Command-Line History

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Adversaries may attempt to clear or disable the Bash command-line history in an attempt to evade detection or forensic investigations.

Rule type: eql

Rule indices:

  • auditbeat-*
  • 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: None

Tags:

  • Domain: Endpoint
  • OS: Linux
  • OS: macOS
  • Use Case: Threat Detection
  • Tactic: Defense Evasion
  • Data Source: Elastic Defend

Version: 103

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

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Rule query

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process where event.type in ("start", "process_started") and
 (
  ((process.args : ("rm", "echo") or
    (process.args : "ln" and process.args : "-sf" and process.args : "/dev/null") or
    (process.args : "truncate" and process.args : "-s0"))
    and process.args : (".bash_history", "/root/.bash_history", "/home/*/.bash_history","/Users/.bash_history", "/Users/*/.bash_history",
                        ".zsh_history", "/root/.zsh_history", "/home/*/.zsh_history", "/Users/.zsh_history", "/Users/*/.zsh_history")) or
  (process.name : "history" and process.args : "-c") or
  (process.args : "export" and process.args : ("HISTFILE=/dev/null", "HISTFILESIZE=0")) or
  (process.args : "unset" and process.args : "HISTFILE") or
  (process.args : "set" and process.args : "history" and process.args : "+o")
 )

Framework: MITRE ATT&CKTM