CVE-2021-21342 is a medium-severity vulnerability affecting Apache XStream prior to version 1.4.16. This vulnerability allows attackers to manipulate the input stream during unmarshalling, potentially leading to server-side forgery requests. XStream, a Java library for serializing and deserializing objects, is widely used, making this vulnerability particularly concerning for applications relying on its functionality.
The vulnerability has a CVSS score of 5.3, indicating a medium level of risk. It is categorized as having a network attack vector with high attack complexity, requiring no privileges for exploitation but necessitating user interaction. Organizations using affected versions should address this vulnerability promptly to prevent potential data integrity issues.
If organizations have not configured XStream's security framework according to recommendations, they are at higher risk. Those relying on the default blacklist settings must upgrade to at least version 1.4.16 to avoid exploitation. The urgency of patching cannot be overstated: organizations should prioritize patching immediately.
Currently, there are no known public exploits for this vulnerability, and it has not been included in the Known Exploited Vulnerabilities (KEV) catalog. However, the potential for exploitation remains, and organizations must remain vigilant.
In summary, the risk to organizations includes potential unauthorized access and manipulation of data through server-side forgery requests, leading to a loss of data integrity. Immediate action is recommended to mitigate these risks.
Vulnerability Details
XStream is a Java library designed for object serialization to XML and back. The vulnerability arises during the unmarshalling process, where type information is included in the processed stream, allowing an attacker to manipulate the input stream. This manipulation can lead to server-side forgery requests. The issue affects all versions prior to 1.4.16, with CVE-2021-21342 specifically documented in security advisories.
The vulnerability is classified under CWE-502 (Deserialization of Untrusted Data) and CWE-918 (Inclusion of Sensitive Information in the Request). The publication date of this CVE was March 23, 2021, and it has undergone analysis since then.
Technical Analysis
The root cause of this vulnerability lies in XStream's handling of type information during the unmarshalling process. Attackers may exploit this by injecting malicious objects into the processed input stream, resulting in unintended object instantiation on the server side.
The attack vector is network-based, requiring the attacker to have access to the network where the XStream service operates. The complexity of the attack is high, as it requires user interaction to trigger the deserialization process. No privileges are required for exploitation, and user interaction is needed to exploit the vulnerability.
In terms of impact, the vulnerability has a confidentiality impact of none, an integrity impact of high, and no availability impact. This means that while the data itself may not be disclosed, its integrity can be compromised.
Risk & Impact Analysis
Organizations using vulnerable versions of XStream may face significant risks, particularly in applications that handle sensitive data. The potential for server-side forgery requests can lead to unauthorized actions being performed on behalf of legitimate users, compromising the security posture of the organization.
The blast radius for this vulnerability can be extensive, particularly for applications that communicate with external services or systems. As such, organizations must assess their exposure to this vulnerability and prioritize remediation based on their risk profile.
Given the CVSS score of 5.3, the urgency for remediation is moderate. Organizations should schedule remediation within their patch management cycles, ensuring that they implement the necessary upgrades and review security configurations.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects all versions of XStream prior to version 1.4.16. Additionally, it impacts various products including Apache ActiveMQ, Apache JMeter, and components from Oracle and Debian, as detailed in the CPE (Common Platform Enumeration) records.
Mitigation & Remediation
To mitigate the vulnerability, organizations should upgrade to XStream version 1.4.16 or later. If a patch is unavailable, consider implementing workarounds such as configuring XStream's security framework with a whitelist of required types to minimize the risk of exploitation.
For additional guidance on securing applications that use XStream, organizations may consider utilizing application security assessment services.
Detection Guidance
Logs should be monitored for unusual requests to the XStream service, particularly those attempting to manipulate type information during unmarshalling. Additionally, organizations should watch for behavioral anomalies that may indicate exploitation attempts.
AppSecure Threat Intelligence Insight
The vulnerability reflected in CVE-2021-21342 highlights the importance of secure coding practices, particularly in libraries that handle serialization. Organizations should remain vigilant about the libraries and frameworks they utilize, ensuring they are kept up to date.
Security teams should consider reviewing their dependency management strategies and implementing regular security assessments to identify vulnerabilities in third-party libraries. This proactive approach can help mitigate risks associated with supply chain attacks.
For more information on securing your applications, organizations can refer to our penetration testing methodology and other relevant resources.
Maintaining a robust security posture requires continuous vigilance and adaptation to the evolving threat landscape. By following best practices and leveraging available resources, organizations can enhance their resilience against exploitation of vulnerabilities such as CVE-2021-21342.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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