What is finalize() Method Without (CWE-568)?

TL;DR: Finalize() Method Without super.finalize() (CWE-568) is a vulnerability where the product’s finalize method does not call super.finalize(), leading to incomplete cleanup and potential resource leaks.

What is finalize() Method Without super.finalize()?

finalize() Method Without super.finalize() (CWE-568) is a type of quality degradation vulnerability that occurs when the product’s finalize method does not call super.finalize(). As defined by the MITRE Corporation under CWE-568, and classified by the OWASP Foundation as Not directly mapped.

Quick Summary

Finalize() Method Without super.finalize() can lead to incomplete cleanup operations, causing potential resource leaks and quality degradation. Jump to: Overview · How It Works · Business Impact · Attack Scenario · Detection · Fixes

Jump to: Quick Summary · finalize() Method Without super.finalize() Overview · How finalize() Method Without super.finalize() Works · Business Impact of finalize() Method Without super.finalize() · finalize() Method Without super.finalize() Attack Scenario · How to Detect finalize() Method Without super.finalize() · How to Fix finalize() Method Without super.finalize() · Framework-Specific Fixes for finalize() Method Without super.finalize() · How to Ask AI to Check Your Code for finalize() Method Without super.finalize() · finalize() Method Without super.finalize() Best Practices Checklist · finalize() Method Without super.finalize() FAQ · Vulnerabilities Related to finalize() Method Without super.finalize() · References · Scan Your Own Site

finalize() Method Without super.finalize() Overview

• What: Finalize() method without calling super.finalize() leads to incomplete cleanup.
• Why it matters: Incomplete cleanup can cause resource leaks, performance degradation, and potential security vulnerabilities.
• Where it occurs: Java, Python, C++ applications that override finalize().
• Who is affected: Developers and organizations using these languages who do not properly implement finalize().
• Who is NOT affected: Applications that adhere to proper cleanup procedures.

How finalize() Method Without super.finalize() Works

Root Cause

The root cause of this issue lies in the failure to call super.finalize() within overridden finalize methods, leading to incomplete resource cleanup.

Attack Flow

1. The garbage collector identifies an object for finalization.
2. The application’s finalize method is invoked but does not call super.finalize().
3. Cleanup operations are skipped or partially completed.
4. Resources remain uncleaned, causing potential issues like memory leaks.

Prerequisites to Exploit

• An overridden finalize() method that omits calling super.finalize().

Vulnerable Code

protected void finalize() {
    // Custom cleanup code here
}

This code lacks a call to super.finalize(), leading to incomplete cleanup operations.

Secure Code

protected void finalize() throws Throwable {
    try {
        // Custom cleanup code here
    } finally {
        super.finalize();
    }
}

Ensuring that super.finalize() is called guarantees proper resource cleanup.

Business Impact of finalize() Method Without super.finalize()

• Confidentiality: No direct impact.
• Integrity: Incomplete cleanup can corrupt data integrity, leading to inconsistent application states.
• Availability: Resource leaks may cause performance degradation or crashes due to uncleaned resources.

Business Consequences:

• Financial losses from system downtime and maintenance costs.
• Compliance issues with regulations requiring proper resource management.
• Reputation damage from poor service quality and reliability.

finalize() Method Without super.finalize() Attack Scenario

1. The garbage collector identifies an object for finalization in the application.
2. The application’s finalize method is invoked but does not call super.finalize().
3. Cleanup operations are skipped or partially completed, leaving resources uncleaned.
4. Over time, resource leaks accumulate and cause performance degradation or crashes.

How to Detect finalize() Method Without super.finalize()

Manual Testing

• Review all overridden finalize methods for the presence of super.finalize() calls.
• Test cleanup operations by simulating garbage collection events.

Automated Scanners (SAST / DAST)

Static analysis tools can detect missing super.finalize() calls, while dynamic testing may be needed to confirm actual resource leaks.

PenScan Detection

PenScan’s ZAP and Nuclei engines actively scan for finalize() method implementations without proper cleanup.

False Positive Guidance

False positives occur when the method is correctly implemented but appears suspicious due to context. Verify that super.finalize() is called in all overridden methods.

How to Fix finalize() Method Without super.finalize()

• Ensure any override of finalize() calls super.finalize().
• Use try-finally blocks to guarantee cleanup operations.
• Regularly review and test finalize method implementations for correctness.

Framework-Specific Fixes for finalize() Method Without super.finalize()

protected void finalize() throws Throwable {
    try {
        // Custom cleanup code here
    } finally {
        super.finalize();
    }
}

Ensure that super.finalize() is called in all overridden methods to prevent incomplete cleanup.

How to Ask AI to Check Your Code for finalize() Method Without super.finalize()

finalize() Method Without super.finalize() Best Practices Checklist

✅ Ensure all overridden finalize methods call super.finalize().

✅ Use try-finally blocks to enforce cleanup operations.

✅ Regularly review finalize method implementations for correctness.

✅ Test cleanup procedures through simulated garbage collection events.

✅ Monitor resource usage and performance metrics for signs of leaks.

finalize() Method Without super.finalize() FAQ

How does the finalize() method work in Java?

The finalize() method is called by the garbage collector when an object is no longer accessible, allowing for cleanup activities before the object is destroyed. However, it should always call super.finalize().

What happens if a finalize() method doesn’t call super.finalize()?

If a finalize() method does not call super.finalize(), important cleanup operations may be skipped, leading to quality degradation and potential resource leaks.

How can I detect finalize() Method Without super.finalize() in my codebase?

Use static analysis tools or manual code reviews to check for the presence of finalize() methods that do not call super.finalize().

What is the impact of finalize() Method Without super.finalize() on system integrity?

It can lead to incomplete cleanup, causing resource leaks and potential security vulnerabilities.

How does finalize() Method Without super.finalize() affect application availability?

Incomplete cleanup may cause performance degradation or crashes due to uncleaned resources.

Can you provide an example of how to fix a finalize() method in Java?

Ensure that any override of the finalize() method calls super.finalize() to complete necessary cleanup activities.

What are some best practices for preventing finalize() Method Without super.finalize() issues?

Always call super.finalize() in overridden methods and regularly review code for proper cleanup procedures.

Vulnerabilities Related to finalize() Method Without super.finalize()

References

• MITRE: CWE-568
• NVD

Scan Your Own Site

Manual code review catches what you know to look for. An automated scan catches what you didn’t. Scan your own website using PenScan to find finalize() Method Without super.finalize() and other risks before an attacker does.