Course

The Code Review Patch challenges provide a practical way to enhance code review skills by presenting both the vulnerable code and the patch that fixes the issue. Participants are encouraged to first attempt to identify the vulnerability on their own. If they struggle or want to confirm their hypothesis, they can then refer to the provided patch (diff file) for validation.

In this specific lab, the focus is on a Java class from the `java.security` package, specifically `MessageDigest.java`. The vulnerable code involves the `isEqual` method, which previously compared two digests directly, potentially revealing timing information. The patch modifies this method to use a time-constant comparison to prevent timing attacks. This exercise emphasizes the importance of secure coding practices and understanding how seemingly minor changes can significantly impact security.