Defenses Against Stored Procedure Attacks

From a defensive point of view, we consider stored procedure attacks to be a “second layer” attack because it requires that you have already penetrated the first layer and gained a level of authority prior to being able to execute. When developing a defensive plan to protect against a second-layer attacks, the general rules are as follows:

1. Try to protect the second layer by ensuring that the second layer is secure.
2. Eliminate the vulnerabilities that are exploited by typical second-layer attacks.
3. Limit the attack surface as much as possible.
4. Log/monitor for attacks and have an active and effective alert system.
5. Do your best to limit the impact and effectiveness of the attacks.

This approach is an important part of a defense-in-depth strategy. The concept of defense-in-depth was covered earlier in this book in Chapter 1, “Windows Operating System – Password Attacks.” The goal is to make it as difficult as possible (or hopefully impossible) for an attacker to execute the attacks we have demonstrated.

Stored procedures provide a good example of this idea. In the following sections, you will see multiple strategies that fall into the same defensive layer, but you will not see any that would fall into the second defensive layer (eliminating the second-layer vulnerabilities). Part of the reason that the stored procedures attacks are the subject of this chapter is that it is not possible to completely eliminate the vulnerability.