This post is part of our SQL Server security blog series, 30 SQL Server Security Checks in 30 Days. We’re publishing a new security check every day in the month of June. Visit our sp_CheckSecurity page to learn about our free SQL Server tool you can download and run to check your own server.
In SQL Server, Agent jobs are a crucial component for automating tasks such as backups, maintenance, and other repetitive operations. While configuring these jobs, one important security consideration often overlooked is the selection of the job owner. By default, the job creator is assigned as the owner, but using user logins as job owners can introduce significant security risks and management challenges. Here’s why it’s best practice to avoid assigning user logins as job owners. For clarity, I am using ‘user logins’ to mean individual accounts and contrasting that to the proposed ideal which is a ‘service account’ meaning business users cannot access it and it is used just for the purpose of owning jobs.
1. Security Risks
When a user login owns a job, the job object has its root of trust with that user. If the user login is compromised, any jobs owned by that account can be manipulated, potentially leading to unauthorized data access or harmful system modifications.
2. Dependency on Individual Users
Using user logins as job owners creates dependencies on individual accounts. If the user leaves the organization and their account is disabled or gets locked due to an expired password it will cause the job to fail leading to operational issues and potential downtime.
3. Simplified Management
Managing SQL Server Agent jobs is more straightforward when using a dedicated, service account. It centralizes control and avoids the complexities of tracking job ownership among various user logins. A service account specifically designated for job ownership can be managed consistently, ensuring reliability and ease of maintenance.
4. Audit and Compliance
From an audit and compliance perspective, having a service account as the job owner provides a clear delineation of responsibilities and minimizes ambiguities. It simplifies auditing processes by ensuring that job ownership is not tied to transient user accounts, making it easier to review and comply with security policies.
SQL Server Agent Job Best Practices
To mitigate the risks and challenges mentioned above, follow these best practices:
- Use a Dedicated Service Account: Create a dedicated SQL Server Agent service account with the necessary permissions to own jobs. Ensure this account has a strong password policy and is closely monitored.
- Regularly Review Job Ownership: Periodically audit job ownership to ensure compliance with security policies and adjust as necessary. I have provided a script below to assist with this audit process. Please keep in mind this script does not look for jobs owned by sa. Ideally, sa would not be used but you can read more about that here. Also, reporting server jobs need to remain owned by the reporting server account that created them.
SELECT
@@SERVERNAME as server_name
, 'Job Owned by User account: [' + j.name + '].' as owner
, '/* Previous Owner ('+suser_sname(owner_sid)+') ' + CASE WHEN IS_SRVROLEMEMBER('sysadmin', SUSER_SNAME(owner_sid)) = 1 Then 'IS SYSADMIN' ELSE 'IS NOT SYSADMIN' END +'*/ USE msdb; EXEC msdb.dbo.sp_update_job @job_name = ' + QUOTENAME(j.name) + ', @owner_login_name = ''<disabled for login sa or a managed job service account>'';' as fix_script
FROM msdb.dbo.sysjobs AS j
INNER JOIN msdb.dbo.syscategories AS C ON j.category_id = C.category_id
WHERE j.owner_sid <> 0x01
AND C.name <> 'Report Server'
/* Previous Owner (TestUser) IS NOT SYSADMIN*/ USE msdb; EXEC msdb.dbo.sp_update_job @job_name = [test], @owner_login_name = '<disabled for login sa or a managed job service account>';
- Implement Least Privilege Principle: Grant the service account the minimum permissions required to perform its duties, reducing potential attack vectors.
By adhering to these guidelines, you can enhance the security and reliability of your SQL Server Agent jobs, ensuring smooth and secure operations. However, there is still one major consideration for you to address:
Taking away ownership of the job will take away the previous owner’s ability to modify the job unless they are a sysadmin already. This will create new overhead, possibly a good time to implement change control and versioning of jobs if it doesn’t already exist in your environment.
As always, please make changes in a test environment first.
