27 Oct Why granting the DBA role is a really bad idea!

Just like any user accounts, database users in Oracle can be granted specific roles. These roles are crucial because they define exactly what a user can do and what data they can access within the database. The security best practice here is the Principle of Least Privilege (PoLP). This means granting users only the specific privileges they absolutely need to perform their job, and nothing more. This significantly improves your database security. 

Oracle provides pre-defined roles to simplify privilege management. One of these, the DBA role, comes with a wide range of powerful privileges intended only for Database Administrators. However, it’s surprisingly common for this powerful DBA role to be granted too liberally. 

Why is this a problem? And what are the potential security risks of overusing the DBA role? Let’s take a closer look. 

The danger of over-granting DBA roles 

Defining the right set of privileges for each user can be a time-consuming task. User needs can change over time due to new application features or evolving job roles. This complexity is often why administrators might be tempted to simply grant the DBA role to users. From the user’s perspective, this often makes things “just work” and avoids the need for constant adjustments to privileges after application changes or updates. 

However, granting the DBA role too broadly carries significant security risks. Here are some key dangers to be aware of: 

• When multiple or even all users have the DBA role, you significantly expand the attack surface. Hackers have more accounts to potentially compromise, which dramatically increases the risk of data breaches. 

• Users with the DBA role can see all data within the database, not just their own. Beyond privacy concerns, this also means users or developers could accidentally delete or modify data that belongs to others, potentially causing serious disruption. 

• The DBA role grants the ability to perform administrative tasks that should be strictly limited to dedicated Database Administrators. This includes actions like creating, deleting, or blocking users, granting privileges to others, and even creating or dropping tables and indexes. Granting these powers widely can lead to instability and security vulnerabilities.
   

A real-world vulnerability example 

The Oracle Patch Update from October 2020 highlighted a real-world example of how misusing the DBA role can be exploited. A bug was discovered that could allow hackers to exploit users with the DBA role (see the advisory). 

This vulnerability, related to a boundary error in a decompression function, could allow a remote attacker to create a malicious archive. If a user with the DBA role was tricked into opening this archive, it could lead to out-of-bounds write errors and even the execution of arbitrary code on the system. This shows the real-world impact of vulnerabilities that can be amplified when powerful roles like DBA are over-granted.
 

DBA vs. SYSDBA: know the difference 

It’s also crucial to distinguish between the DBA role and the SYSDBA system privilege. The SYSDBA system privilege is even more powerful than the DBA role. With SYSDBA, a user can start and stop the entire database instance, and in the worst-case scenario, even remove the database altogether. This privilege also allows actions like creating a new spfile, changing the archivelog mode, and performing database recovery. 

The SYSDBA privilege should be granted extremely sparingly, ideally only to truly essential administrators. Consider leaving it exclusively granted to the SYS user, making sure that the SYS account has a strong, complex password and is carefully audited.
 

Identifying users with the DBA role 

Hopefully, it’s now clear why granting the DBA role indiscriminately is a significant security risk. You’re probably wondering how to identify which users in your Oracle database currently have this role. You can use the following SQL query to list all users with the DBA role (excluding SYS and SYSTEM accounts): 

select grantee from dba_role_privs where granted_role=’DBA’ and grantee not in (‘SYS’,’SYSTEM’) order by 1; 

Refining privileges with “capture privilege” 

Once you have a list of users with the DBA role, the next step is to determine the necessary privileges for each of these users. Oracle offers a helpful feature called “Capture Privilege” to simplify this process. This feature, available from Oracle 19c Enterprise Edition onwards (and in Database Vault option before 19c), allows you to capture real-time information on the privileges and roles actually used by users on the system. 

By using Capture Privilege, you can gain insights into the actual privileges users need. You can then revoke unused grants and adjust roles to more accurately reflect the access each user truly requires, adhering to the Principle of Least Privilege. For Standard Edition users or older versions, other techniques will be needed to determine necessary privileges.
 

Expert help for oracle security 

Granting the DBA role too freely is a common shortcut, but it introduces significant security risks into your Oracle database environment. Understanding the Principle of Least Privilege and actively managing user roles is crucial for strong database security. 

Need help identifying users with the DBA role in your Oracle system? Want expert assistance in determining the necessary privileges for your users and implementing best practices? Or perhaps you’re interested in setting up the Oracle Capture Privilege feature to streamline privilege management? 

Our Monin database experts are here to assist you. We can also provide a comprehensive security assessment to give you deeper insights into how to enhance your overall database security posture. 

Get in touch with us today to discuss your Oracle security needs!