CWE-584: Return Inside Finally Block
Learn about CWE-584 (Return Inside Finally Block), its security impact, exploitation methods, and prevention guidelines.
What is Return Inside Finally Block?
• Overview: The "Return Inside Finally Block" vulnerability occurs when a return statement is placed within a finally block in code. This can lead to any exceptions thrown in the try block being ignored, as the return statement in the finally block will override the exception handling process.
• Exploitation Methods:
- Attackers may not directly exploit this vulnerability; however, it could lead to unintended code behavior, allowing potential bypass of error handling mechanisms.
- Common attack patterns include inducing exceptions in the try block that are not properly handled due to the return statement in the finally block, potentially leading to inconsistent application states.
• Security Impact:
- Direct consequences include suppression of exceptions, causing error handling routines to be bypassed, and leading to unexpected application behavior.
- Potential cascading effects involve loss of error context, making debugging and maintaining the code more difficult, and possibly leading to security loopholes.
- Business impact could include system instability, data corruption, or loss of customer trust due to unhandled exceptions leading to application crashes or erratic behavior.
• Prevention Guidelines:
- Specific code-level fixes involve avoiding return statements in finally blocks and handling all exceptions in the catch block or after the try-catch-finally structure.
- Security best practices include thorough testing and code reviews to ensure exception handling is correctly implemented and that finally blocks do not alter the control flow unexpectedly.
- Recommended tools and frameworks involve using static code analysis tools that can automatically detect and warn about return statements in finally blocks, such as SonarQube or FindBugs for Java.
Technical Details
Likelihood of Exploit: Not specified
Affected Languages: Not specified
Affected Technologies: Not specified