Sigma rule: CVE-2021-3156 Exploitation Attempt

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-5a93e7cbac81, updated 2023-03-24T00:00:00.000Z.

Rule

Title
CVE-2021-3156 Exploitation Attempt
Status
unsupported
Level
high
Author
Bhabesh Raj
Date
2021/02/01
Modified
2023/03/24
File
unsupported/linux/lnx_auditd_cve_2021_3156_sudo_buffer_overflow.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects exploitation attempt of vulnerability described in CVE-2021-3156.
Alternative approach might be to look for flooding of auditd logs due to bruteforcing
required to trigger the heap-based buffer overflow.

Log source

product
linux
service
auditd

Detection

cmd_base:
    type: 'EXECVE'
    a0: '/usr/bin/sudoedit'
cmd_s:
    - a1: '-s'
    - a2: '-s'
    - a3: '-s'
    - a4: '-s'
cmd_backslash:
    - a1: '\'
    - a2: '\'
    - a3: '\'
    - a4: '\'
condition: all of cmd_* | count() by host > 50

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.privilege_escalation
  • attack.t1068
  • cve.2021.3156

CVEs this rule names

MITRE ATT&CK ids this rule names

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/unsupported/linux/lnx_auditd_cve_2021_3156_sudo_buffer_overflow.yml

Sources and licences

  • SigmaHQ

    "CVE-2021-3156 Exploitation Attempt" by Bhabesh Raj (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/unsupported/linux/lnx_auditd_cve_2021_3156_sudo_buffer_overflow.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: CVE-2021-3156 Exploitation Attempt",
entity page, dataset version ref-5a93e7cbac81, updated 2023-03-24T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/5ee37487-4eb8-4ac2-9be1-d7d14cdc559f (accessed 2026-11-03).
Underlying source: SigmaHQ rule 5ee37487-4eb8-4ac2-9be1-d7d14cdc559f, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.