ASLR Disabled Via Sysctl or Direct Syscall - Linux — Sigma Rule

Rule metadata and linked tags

Author: Milad Cheraghi. Source status: experimental; severity: high. Source dates: 2025-05-26 / 2025-12-05.

{
  "product": "linux",
  "service": "auditd"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 8cb6126e08ec525a251233123bd6eda62e160dbf14490c0834a53d4bfcf0d8ee

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: ASLR Disabled Via Sysctl or Direct Syscall - Linux
id: e497a24e-9345-4a62-9803-b06d7d7cb132
status: experimental
description: |
    Detects actions that disable Address Space Layout Randomization (ASLR) in Linux, including:
      - Use of the `personality` syscall with the ADDR_NO_RANDOMIZE flag (0x0040000)
      - Modification of the /proc/sys/kernel/randomize_va_space file
      - Execution of the `sysctl` command to set `kernel.randomize_va_space=0`
    Disabling ASLR is often used by attackers during exploit development or to bypass memory protection mechanisms.
    A successful use of these methods can reduce the effectiveness of ASLR and make memory corruption attacks more reliable.
references:
    - https://github.com/CheraghiMilad/bypass-Neo23x0-auditd-config/blob/f1c478a37911a5447d5ffcd580f22b167bf3df14/personality-syscall/README.md
    - https://man7.org/linux/man-pages/man2/personality.2.html
    - https://manual.cs50.io/2/personality
    - https://linux-audit.com/linux-aslr-and-kernelrandomize_va_space-setting/
author: Milad Cheraghi
date: 2025-05-26
modified: 2025-12-05
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.defense-impairment
    - attack.t1685
    - attack.t1055.009
logsource:
    product: linux
    service: auditd
detection:
    selection_syscall:
        type: 'SYSCALL'
        SYSCALL: 'personality'
        a0: 40000
    selection_sysctl:
        type: 'EXECVE'
        a0: 'sysctl'
        a1: '-w'
        a2: 'kernel.randomize_va_space=0' # 0 = disable
    condition: 1 of selection_*
falsepositives:
    - Debugging or legitimate software testing
level: high

Original YAML and metadata in JSON

False positives

• Debugging or legitimate software testing

Source references

• https://github.com/CheraghiMilad/bypass-Neo23x0-auditd-config/blob/f1c478a37911a5447d5ffcd580f22b167bf3df14/personality-syscall/README.md
• https://man7.org/linux/man-pages/man2/personality.2.html
• https://manual.cs50.io/2/personality
• https://linux-audit.com/linux-aslr-and-kernelrandomize_va_space-setting/