User Added To Admin Group Via Sysadminctl

Status: test
Severity: medium
Log source: category process_creation, product macos
Author: Sohan G (D4rkCiph3r)
Source: github.com/SigmaHQ/sigma

Detects attempts to create and add an account to the admin group via "sysadminctl"

Known false positives

Legitimate administration activities

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1078.003` Valid Accounts: Local Accounts
Persistence	`T1078.003` Valid Accounts: Local Accounts
Privilege Escalation	`T1078.003` Valid Accounts: Local Accounts
Stealth	`T1078.003` Valid Accounts: Local Accounts

Telemetry coverage

Platform	Record / event type
macOS	ESF event `exec` (NOTIFY): Fires after execve(2) or posix_spawn(2) succeeds, delivering a post-fact record of the new process.

Rule body

title: User Added To Admin Group Via Sysadminctl
id: 652c098d-dc11-4ba6-8566-c20e89042f2b
related:
    - id: 0c1ffcf9-efa9-436e-ab68-23a9496ebf5b
      type: obsolete
status: test
description: Detects attempts to create and add an account to the admin group via "sysadminctl"
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1078.003/T1078.003.md#atomic-test-3---create-local-account-with-admin-privileges-using-sysadminctl-utility---macos
    - https://ss64.com/osx/sysadminctl.html
author: Sohan G (D4rkCiph3r)
date: 2023-03-19
tags:
    - attack.persistence
    - attack.initial-access
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1078.003
logsource:
    category: process_creation
    product: macos
detection:
    selection:
        # Creates and adds new user to admin group
        Image|endswith: '/sysadminctl'
        CommandLine|contains|all:
            - ' -addUser '
            - ' -admin '
    condition: selection
falsepositives:
    - Legitimate administration activities
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    Image|endswith: '/sysadminctl'
    CommandLine|contains|all:
        - ' -addUser '
        - ' -admin '

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`-addUser` `-admin`	`field:"CommandLine" kind:match`
`Image`	ends_with	`/sysadminctl`	`field:"Image" kind:ends_with value:"/sysadminctl"`

User Added To Admin Group Via Sysadminctl

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`