Elastic Security Detection Rules

Shell History Clearing via Environment Variables

Last updated 2 months ago on 2026-04-09
Created 2 months ago on 2026-04-09

About

This rule detects the clearing of the shell history via environment variables. Attackers may clear the shell history to hide their activities from being tracked. By leveraging environment variables such as HISTSIZE, HISTFILESIZE, HISTCONTROL, and HISTFILE, attackers can clear the shell history by setting them to 0, ignoring spaces, or redirecting the history to /dev/null, effectively erasing the command history.
Tags
Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: Defense EvasionData Source: Elastic DefendLanguage: eql
Severity
high
Risk Score
73
MITRE ATT&CK™

Defense Evasion (TA0005)(external, opens in a new tab or window)

↳ Indicator Removal (T1070)(external, opens in a new tab or window)

License
Elastic License v2(external, opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.process*
Related Integrations

endpoint(external, opens in a new tab or window)

Query
text code block:
process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and
process.env_vars like~ (
  "HISTSIZE=0", "HISTFILESIZE=0", "HISTCONTROL=ignorespace", "HISTFILE=/dev/null"
)

Install detection rules in Elastic Security

Detect Shell History Clearing via Environment Variables in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(external, opens in a new tab or window).