Elastic Security Detection Rules

GRUB Configuration Generation through Built-in Utilities

Last updated 9 months ago on 2025-03-20
Created a year ago on 2025-01-16

About

This rule detects the generation of a new GRUB configuration file using built-in Linux commands. The GRUB configuration file is used to configure the GRUB bootloader, which is responsible for loading the Linux kernel and initramfs image during the boot process. Attackers may use these built-in utilities to generate a new GRUB configuration file that includes malicious kernel parameters or boot options, which can be leveraged to maintain persistence on the system.
Tags
Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: PersistenceData Source: Elastic EndgameData Source: Elastic DefendData Source: CrowdstrikeData Source: SentinelOneLanguage: eql
Severity
low
Risk Score
21
MITRE ATT&CK™

Persistence (TA0003)(external, opens in a new tab or window)

↳ Pre-OS Boot (T1542)(external, opens in a new tab or window)

↳ Create or Modify System Process (T1543)(external, opens in a new tab or window)

↳ Hijack Execution Flow (T1574)(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*endgame-*logs-crowdstrike.fdr*logs-sentinel_one_cloud_funnel.*
Related Integrations

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

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

sentinel_one_cloud_funnel(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 in ("exec", "exec_event", "start", "ProcessRollup2") and
process.parent.executable != null and process.name in ("grub-mkconfig", "grub2-mkconfig", "update-grub") and not (
  process.parent.name in ("run-parts", "sudo", "update-grub", "pacman", "dockerd", "dnf", "rpm", "yum") or
  process.parent.executable like~ (
    "/var/lib/dpkg/info/*", "/usr/lib/bootloader/grub2-efi/config", "/tmp/newroot/*", "/usr/lib/kernel/install.d/*"
  )
)

Install detection rules in Elastic Security

Detect GRUB Configuration Generation through Built-in Utilities 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).