Arbitrary Code Execution Vulnerability in Jython: CVE-2016-4000
Summary
CVE-2016-4000: Jython before 2.7.1rc1 allows attackers to execute arbitrary code via a crafted serialized PyFunction object. Affects jython versions < 2.5.3-17. Fixed in 2.5.3-17. How to fix ↓
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Background
Jython is an implementation of the Python programming language designed to run on the Java platform. It allows seamless integration of Java and Python, enabling developers to use Java libraries in Python code. Jython is widely used in various applications for scripting and automation. However, prior to version 2.7.1rc1, Jython was vulnerable to a critical security flaw that could allow attackers to execute arbitrary code through a specially crafted serialized PyFunction object.
Vulnerability Detail
CVE-2016-4000 is a vulnerability in Jython that allows attackers to execute arbitrary code by exploiting a crafted serialized PyFunction object. This vulnerability arises from improper handling of serialized objects, which can lead to remote code execution. Attackers can leverage this flaw to gain unauthorized access to the system, potentially leading to data breaches, system compromise, and further exploitation of the affected environment. The CVSS score for this vulnerability is 9.8, indicating a critical severity level.
How To Fix
Minimum fixed version
2.5.3-17
This is the first release that contains the fix.
sudo apt-get install --only-upgrade jythonTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If upgrading is not immediately possible, consider implementing strict input validation and sanitization for any serialized PyFunction objects. Additionally, avoid deserializing untrusted data and limit the use of Jython in environments where security is a critical concern.
Conclusion
CVE-2016-4000 is a critical vulnerability in Jython that allows for arbitrary code execution through crafted serialized objects. Users are strongly advised to upgrade to the latest version to mitigate risks. For those unable to upgrade immediately, implementing workarounds can provide temporary protection.
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FAQ
CVE-2016-4000 is a vulnerability in Jython that allows arbitrary code execution through crafted serialized PyFunction objects.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without any signup.
The vulnerability can lead to unauthorized access, data breaches, and system compromise, allowing attackers to execute arbitrary code on the affected system.
The recommended action is to upgrade Jython to version 2.5.3-17 or later to eliminate the vulnerability.
Yes, implementing strict input validation and avoiding deserialization of untrusted data can provide temporary protection until an upgrade is performed.
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