CVE-2022-41966 Explained : Impact and Mitigation

XStream Denial of Service via stack overflow.

Understanding CVE-2022-41966

XStream serializes Java objects to XML and back again. Versions prior to 1.4.20 may allow a remote attacker to terminate the application with a stack overflow error, resulting in a denial of service only via manipulation the processed input stream. The attack uses the hash code implementation for collections and maps to force recursive hash calculation causing a stack overflow. This issue is patched in version 1.4.20 which handles the stack overflow and raises an InputManipulationException instead. A potential workaround for users who only use HashMap or HashSet and whose XML refers these only as the default map or set, is to change the default implementation of java.util.Map and java.util per the code example in the referenced advisory. However, this implies that your application does not care about the implementation of the map, and all elements are comparable.

What is CVE-2022-41966?

CVE-2022-41966 is a vulnerability in XStream, where versions prior to 1.4.20 are susceptible to a denial of service attack via a stack overflow initiated by manipulating the input stream.

The Impact of CVE-2022-41966

The impact of this vulnerability is that a remote attacker can exploit it to cause a denial of service condition in the application, leading to service unavailability.

Technical Details of CVE-2022-41966

XStream's vulnerability lies in how it handles serialization of Java objects to XML, with affected versions being those before 1.4.20.

Vulnerability Description

The vulnerability allows an attacker to trigger a stack overflow by manipulating the input stream, leading to the termination of the application and denial of service.

Affected Systems and Versions

Only XStream versions prior to 1.4.20 are impacted by this vulnerability.

Exploitation Mechanism

The attack leverages the hash code implementation for collections and maps to induce recursive hash calculation, causing a stack overflow.

Mitigation and Prevention

To mitigate the risks associated with CVE-2022-41966, it is essential to take immediate steps and adopt long-term security practices.

Immediate Steps to Take

Update XStream to version 1.4.20 to patch the vulnerability and protect the application from stack overflow attacks leading to a denial of service.

Long-Term Security Practices

Regularly update software components and libraries to ensure that known vulnerabilities are addressed promptly and the overall security posture of the application is enhanced.

Patching and Updates

Stay informed about security advisories and updates from XStream to apply patches and improvements that safeguard the application against potential threats.