Creation Of An User Account — Sigma Rule

Rule metadata and linked tags

Author: Marie Euler, Pawel Mazur. Source status: test; severity: medium. Source dates: 2020-05-18 / 2022-12-20.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: b65ae8b342d4f0ec2603a65cda8a6762dad58a8ecdc8fd0ddf097e885d6cde4f

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: Creation Of An User Account
id: 759d0d51-bc99-4b5e-9add-8f5b2c8e7512
status: test
description: Detects the creation of a new user account. Such accounts may be used for persistence that do not require persistent remote access tools to be deployed on the system.
references:
    - https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/security_guide/sec-understanding_audit_log_files
    - https://access.redhat.com/articles/4409591#audit-record-types-2
    - https://www.youtube.com/watch?v=VmvY5SQm5-Y&ab_channel=M45C07
author: Marie Euler, Pawel Mazur
date: 2020-05-18
modified: 2022-12-20
tags:
    - attack.t1136.001
    - attack.persistence
logsource:
    product: linux
    service: auditd
detection:
    selection_syscall_record_type:
        type: 'SYSCALL'
        exe|endswith: '/useradd'
    selection_add_user_record_type:
        type: 'ADD_USER' # This is logged without having to configure audit rules on both Ubuntu and Centos
    condition: 1 of selection_*
falsepositives:
    - Admin activity
level: medium

Original YAML and metadata in JSON

False positives

• Admin activity

Source references

• https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/security_guide/sec-understanding_audit_log_files
• https://access.redhat.com/articles/4409591#audit-record-types-2
• https://www.youtube.com/watch?v=VmvY5SQm5-Y&ab_channel=M45C07