What is finalize() Method Declared Public (CWE-583)?

TL;DR: Finalize() Method Declared Public (CWE-583) is a security vulnerability in Java where the finalize() method is declared public, allowing direct invocation by attackers. This exposes applications to unauthorized code execution and resource leaks, compromising system integrity and availability. Ensure that finalize() methods are protected and not exposed publicly.

What is finalize() Method Declared Public?

finalize() Method Declared Public (CWE-583) is a type of security vulnerability that occurs when the finalize() method in Java is declared public. As defined by the MITRE Corporation under CWE-583, and classified by the OWASP Foundation under no direct mapping…

Quick Summary

Finalize() Method Declared Public (CWE-583) exposes applications to unauthorized code execution and resource leaks when the finalize() method in Java is declared public. This can lead to significant security risks such as data modification, denial of service, and unauthorized access. Jump to: What is finalize() Method Declared Public? · Quick Summary · Overview · How It Works · Business Impact · Attack Scenario · Detection · Fix · Framework-Specific Fixes · AI Check Prompt · Best Practices Checklist · FAQ · Related Vulnerabilities

Jump to: Quick Summary · finalize() Method Declared Public Overview · How finalize() Method Declared Public Works · Business Impact of finalize() Method Declared Public · finalize() Method Declared Public Attack Scenario · How to Detect finalize() Method Declared Public · How to Fix finalize() Method Declared Public · Framework-Specific Fixes for finalize() Method Declared Public · How to Ask AI to Check Your Code for finalize() Method Declared Public · finalize() Method Declared Public Best Practices Checklist · finalize() Method Declared Public FAQ · Vulnerabilities Related to finalize() Method Declared Public · References · Scan Your Own Site

finalize() Method Declared Public Overview

What: Finalize() Method Declared Public (CWE-583) is a security vulnerability in Java where the finalize() method is declared public, allowing direct invocation by attackers.

Why it matters: This exposes applications to unauthorized code execution and resource leaks, compromising system integrity and availability.

Where it occurs: In Java applications that improperly expose finalize() methods publicly.

Who is affected: Applications using Java with improperly exposed finalize() methods are at risk.

Who is NOT affected: Systems adhering to secure coding practices by declaring finalize() as protected or private are not vulnerable.

How finalize() Method Declared Public Works

Root Cause

The root cause of this vulnerability lies in the improper declaration of the finalize() method as public, allowing direct invocation by attackers.

Attack Flow

1. An attacker identifies a publicly exposed finalize() method.
2. The attacker invokes the finalize() method directly.
3. Unauthorized code execution or resource leaks occur due to the lack of proper access control.

Prerequisites to Exploit

• The finalize() method must be declared public.
• The attacker needs to have knowledge of this vulnerability and the ability to invoke the method.

Vulnerable Code

public class Example {
    public void finalize() throws Throwable {
        // Dangerous operation
    }
}

This code demonstrates a finalize() method declared as public, which allows direct invocation by attackers.

Secure Code

protected void finalize() throws Throwable {
    // Safe operations or no dangerous actions
}

The secure version ensures that the finalize() method is protected and not exposed publicly.

Business Impact of finalize() Method Declared Public

Confidentiality: Attackers can execute arbitrary code, potentially accessing sensitive data.

• Example: Unauthorized access to confidential information stored in memory.

Integrity: Resource leaks or unauthorized modifications can occur.

• Example: Data corruption due to improper resource handling.

Availability: Denial of service attacks may be possible.

• Example: System crashes due to excessive resource consumption.

Business Consequences

• Financial losses from data breaches and system downtime.
• Non-compliance with regulatory standards such as GDPR, HIPAA, or PCI-DSS.
• Reputational damage from publicized security incidents.

finalize() Method Declared Public Attack Scenario

1. An attacker identifies a Java application exposing finalize() methods publicly.
2. The attacker sends crafted requests to invoke the exposed method.
3. Unauthorized code execution occurs, leading to resource leaks or data modification.
4. System integrity and availability are compromised due to unauthorized actions.

How to Detect finalize() Method Declared Public

Manual Testing

• Review Java classes for public finalize() methods.
• Ensure that no direct invocations of the method are possible.
• Verify that all instances use protected or private access modifiers.

Automated Scanners (SAST / DAST)

Static analysis tools can detect publicly exposed finalize() methods. Dynamic testing may be necessary to confirm actual exploitation scenarios.

PenScan Detection

PenScan’s scanner engines, such as ZAP and Nuclei, actively test for this vulnerability by identifying public finalize() methods in Java applications.

False Positive Guidance

A false positive occurs if a method is marked as public but does not contain any dangerous operations. Ensure that the finalize() method is indeed accessible to attackers before marking it as vulnerable.

How to Fix finalize() Method Declared Public

• Change the access modifier of finalize() methods from public to protected.
• Ensure that no direct invocations of the finalize() method are possible.
• Implement proper resource management and cleanup mechanisms within the method.
• Review and update existing code to adhere to secure coding practices.

Framework-Specific Fixes for finalize() Method Declared Public

Java

protected void finalize() throws Throwable {
    // Safe operations or no dangerous actions
}

Ensure that all finalize() methods are declared protected in Java applications to prevent direct invocation by attackers.

How to Ask AI to Check Your Code for finalize() Method Declared Public

finalize() Method Declared Public Best Practices Checklist

✅ Ensure that finalize() methods are declared as protected. ✅ Review all instances of finalize() to ensure no public declarations exist. ✅ Implement proper resource management within the method. ✅ Conduct regular security audits and reviews.

finalize() Method Declared Public FAQ

How does declaring a finalize() method public in Java expose an application to security risks?

Declaring the finalize() method public allows attackers to invoke it directly, potentially executing arbitrary code or causing resource leaks.

What are the typical consequences of CWE-583 vulnerabilities?

CWE-583 can lead to unauthorized code execution and data modification, compromising confidentiality, integrity, and availability.

How do you detect finalize() Method Declared Public in your Java application?

Use static analysis tools or manual review to check for public finalize() methods. PenScan’s automated scanners can also identify such vulnerabilities.

What is the best way to prevent CWE-583 in a Java application?

Ensure that finalize() methods are declared protected and not exposed publicly, adhering to secure coding practices.

Can you provide an example of vulnerable code for finalize() Method Declared Public?

A public finalize() method allows attackers to invoke it directly, potentially executing arbitrary code or causing resource leaks.

How can I fix a finalize() Method Declared Public vulnerability in my Java application?

Change the access modifier from public to protected and ensure that finalize() methods are not exposed publicly.

What is the impact of CWE-583 on system availability?

CWE-583 can lead to resource exhaustion or denial-of-service attacks, impacting system availability.

Vulnerabilities Related to finalize() Method Declared Public

References

• MITRE: CWE-583
• 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 Declared Public and other risks before an attacker does.