MSSQL Add Account To Sysadmin Role

Description

Detects when an attacker tries to backdoor the MSSQL server by adding a backdoor account to the sysadmin fixed server role

Query · sigma

selection:
  Provider_Name|contains: MSSQL
  EventID: 33205
  Data|contains|all:
  - object_name:sysadmin
  - 'statement:alter server role [sysadmin] add member '
condition: selection

Known false positives

  • Rare legitimate administrative activity
Raw source MSSQL Add Account To Sysadmin Role · Sigma
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Published by SigmaHQ/sigma ↗, licensed under Detection Rule License 1.1 ↗. Reproduced here unmodified. 
title: MSSQL Add Account To Sysadmin Role
id: 08200f85-2678-463e-9c32-88dce2f073d1
status: test
description: Detects when an attacker tries to backdoor the MSSQL server by adding a backdoor account to the sysadmin fixed server role
references:
    - https://www.netspi.com/blog/technical/network-penetration-testing/sql-server-persistence-part-1-startup-stored-procedures/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-07-13
modified: 2024-06-26
tags:
    - attack.persistence
logsource:
    product: windows
    service: application
    definition: 'Requirements: MSSQL audit policy must be enabled in order to receive this event in the application log'
    # warning: The 'data' field used in the detection section is the container for the event data as a whole. You may have to adapt the rule for your backend accordingly
detection:
    selection:
        Provider_Name|contains: 'MSSQL' # Note: We use contains to account for other third party providers - See https://github.com/SigmaHQ/sigma/issues/4876
        EventID: 33205
        Data|contains|all:
            - 'object_name:sysadmin'
            - 'statement:alter server role [sysadmin] add member '
    condition: selection
falsepositives:
    - Rare legitimate administrative activity
level: high

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