Sigma Rule Library

MSSQL Disable Audit Settings

Detects when an attacker calls the "ALTER SERVER AUDIT" or "DROP SERVER AUDIT" transaction in order to delete or disable audit logs on the server

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Detection logic

selection

Provider_Name|contains: MSSQL
EventID: 33205
Data|contains:
  - statement:ALTER SERVER AUDIT
  - statement:DROP SERVER AUDIT

Condition

selection

Raw YAML

title: MSSQL Disable Audit Settings
id: 350dfb37-3706-4cdc-9e2e-5e24bc3a46df
status: test
description: Detects when an attacker calls the "ALTER SERVER AUDIT" or "DROP SERVER AUDIT" transaction in order to delete or disable audit logs on the server
references:
    - https://www.netspi.com/blog/technical/network-penetration-testing/sql-server-persistence-part-1-startup-stored-procedures/
    - https://learn.microsoft.com/en-us/sql/t-sql/statements/drop-server-audit-transact-sql?view=sql-server-ver16
    - https://learn.microsoft.com/en-us/sql/t-sql/statements/alter-server-audit-transact-sql?view=sql-server-ver16
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-07-13
modified: 2024-06-26
tags:
    - attack.defense-impairment
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:
            - 'statement:ALTER SERVER AUDIT'
            - 'statement:DROP SERVER AUDIT'
    condition: selection
falsepositives:
    - This event should only fire when an administrator is modifying the audit policy. Which should be a rare occurrence once it's set up
level: high

False positives

  • This event should only fire when an administrator is modifying the audit policy. Which should be a rare occurrence once it's set up

References