Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.
CWE-498 Variant Draft
Cloneable Class Containing Sensitive Information
This vulnerability occurs when a class containing sensitive information, such as credentials or personal data, is made cloneable. Attackers can bypass normal initialization and access the sensitive…
Definition
What is CWE-498?
This vulnerability occurs when a class containing sensitive information, such as credentials or personal data, is made cloneable. Attackers can bypass normal initialization and access the sensitive data by creating a copy of the object.
When a class implements the Cloneable interface without proper safeguards, it effectively becomes an open book. The clone() method can create copies of the object without calling its constructor, allowing any other class in the application to duplicate instances and directly access their internal, sensitive fields. This bypasses any security checks or initialization logic you might have placed in the constructor.
To prevent this, you should explicitly deny cloning for classes that handle sensitive data. You can achieve this by declaring a clone() method that throws a CloneNotSupportedException. This simple step ensures your object's internal state remains controlled and prevents unintended data exposure through object duplication.
Real-world impact
Real-world CVEs caused by CWE-498
No public CVE references are linked to this CWE in MITRE's catalog yet.
How attackers exploit it
Step-by-step attacker path
- 1
Identify a code path that handles untrusted input without validation.
- 2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
- 3
Deliver the payload through a normal request and observe the application's reaction.
- 4
Iterate until the response leaks data, executes attacker code, or escalates privileges.
Vulnerable code example
Vulnerable Java
The following example demonstrates the weakness.
public class CloneClient {
public CloneClient() //throws
java.lang.CloneNotSupportedException {
Teacher t1 = new Teacher("guddu","22,nagar road");
//...
// Do some stuff to remove the teacher.
Teacher t2 = (Teacher)t1.clone();
System.out.println(t2.name);
}
public static void main(String args[]) {
new CloneClient();
}
}
class Teacher implements Cloneable {
public Object clone() {
try {
return super.clone();
}
catch (java.lang.CloneNotSupportedException e) {
throw new RuntimeException(e.toString());
}
}
public String name;
public String clas;
public Teacher(String name,String clas) {
this.name = name;
this.clas = clas;
}
} Secure code example
Secure Java
Make classes uncloneable by defining a clone function like:
public final void clone() throws java.lang.CloneNotSupportedException {
throw new java.lang.CloneNotSupportedException();
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-498
- Implementation If you do make your classes clonable, ensure that your clone method is final and throw super.clone().
Detection signals
How to detect CWE-498
Run dynamic application security testing against the live endpoint.
Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.
Code review: flag any new code that handles input from this surface without using the validated framework helpers.
Plexicus auto-detects CWE-498 and opens a fix PR in under 60 seconds.
Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.
Frequently asked questions What is CWE-498?
How serious is CWE-498?
What languages or platforms are affected by CWE-498?
How can I prevent CWE-498?
How does Plexicus detect and fix CWE-498?
Where can I learn more about CWE-498?
Frequently asked questions
What is CWE-498?
This vulnerability occurs when a class containing sensitive information, such as credentials or personal data, is made cloneable. Attackers can bypass normal initialization and access the sensitive data by creating a copy of the object.
How serious is CWE-498?
MITRE rates the likelihood of exploit as Medium — exploitation is realistic but typically requires specific conditions.
What languages or platforms are affected by CWE-498?
MITRE lists the following affected platforms: C++, Java, C#.
How can I prevent CWE-498?
If you do make your classes clonable, ensure that your clone method is final and throw super.clone().
How does Plexicus detect and fix CWE-498?
Plexicus's SAST engine matches the data-flow signature for CWE-498 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-498?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/498.html. You can also reference OWASP and NIST documentation for adjacent guidance.
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