CVE-2021-39146 Explained : Impact and Mitigation

XStream, a simple library for object serialization to XML and back again, has a vulnerability that may lead to arbitrary code execution.

Understanding CVE-2021-39146

XStream is susceptible to an Arbitrary Code Execution attack due to a security flaw present in affected versions. This CVE poses a significant risk to systems utilizing the XStream library.

What is CVE-2021-39146?

XStream, an XML serialization library, is vulnerable to an Arbitrary Code Execution attack in versions < 1.4.18. Exploiting this vulnerability could enable a remote attacker to execute arbitrary code by manipulating the input stream.

The Impact of CVE-2021-39146

The vulnerability has a CVSS v3.1 base score of 8.5, indicating a high severity issue with significant confidentiality, integrity, and availability impacts. The attack complexity is high, with a network attack vector and low privileges required.

Technical Details of CVE-2021-39146

XStream's vulnerability to Arbitrary Code Execution provides insight into the specific aspects of the issue.

Vulnerability Description

The flaw allows an attacker to load and execute arbitrary code from a remote host by manipulating the input stream. Users who followed the security recommendations to set up XStream's whitelist are not affected.

Affected Systems and Versions

Product: XStream
Vendor: x-stream
Versions Affected: < 1.4.18

Exploitation Mechanism

The vulnerability can be exploited by an attacker manipulating the processed input stream to execute arbitrary code remotely.

Mitigation and Prevention

Protecting systems from the CVE-2021-39146 vulnerability involves taking immediate steps and implementing long-term security practices.

Immediate Steps to Take

Update XStream to version 1.4.18 or above to mitigate the vulnerability.
Apply network controls to limit access to potentially vulnerable systems.
Monitor and analyze network traffic for signs of exploitation.

Long-Term Security Practices

Implement secure coding practices to prevent code injection vulnerabilities.
Conduct regular security assessments and code reviews to identify and address potential weaknesses.

Patching and Updates

Regularly update XStream and other dependencies to patch known vulnerabilities.
Stay informed about security advisories and updates from the XStream vendor to address new threats in a timely manner.