Discover the impact of CVE-2021-21249 on OneDev versions prior to 4.0.3, allowing post-auth remote code execution. Learn about the vulnerability and mitigation steps.
OneDev is an all-in-one devops platform with a vulnerability (CVE-2021-21249) that affects versions prior to 4.0.3. The issue involves YAML parsing, potentially leading to post-auth remote code execution through SnakeYaml. This critical vulnerability was addressed in version 4.0.3 by restricting class deserialization.
Understanding CVE-2021-21249
This section will cover the details of CVE-2021-21249, including its impact, technical details, and mitigation strategies.
What is CVE-2021-21249?
CVE-2021-21249 is a security vulnerability in OneDev versions before 4.0.3 that allows post-auth remote code execution due to unsafe YAML deserialization. Attackers can exploit this issue to instantiate arbitrary classes, leading to potential code execution.
The Impact of CVE-2021-21249
With a CVSS score of 9.6 (Critical), this vulnerability has a severe impact on confidentiality and integrity. An attacker can exploit it over a network with low privileges required, potentially altering system integrity and compromising sensitive data.
Technical Details of CVE-2021-21249
Let's delve into the technical aspects of CVE-2021-21249, exploring the vulnerability description, affected systems, and the exploitation mechanism.
Vulnerability Description
The vulnerability arises from insecure YAML parsing in OneDev, allowing the instantiation of arbitrary classes. This can be exploited by an attacker for post-auth remote code execution by loading user-controlled classes.
Affected Systems and Versions
OneDev versions prior to 4.0.3 are affected by this vulnerability. Users of these versions are at risk of exploitation and are advised to upgrade to the patched version.
Exploitation Mechanism
By leveraging SnakeYaml's YAML parsing, attackers can instantiate arbitrary classes like
javax.script.ScriptEngineManager
, enabling them to execute arbitrary code post-authentication.
Mitigation and Prevention
Protecting your system against CVE-2021-21249 is crucial. Here are some immediate steps and long-term security practices to consider:
Immediate Steps to Take
Long-Term Security Practices
Patching and Updates
Stay informed about security patches and updates released by OneDev. Apply them promptly to ensure that your system is protected against known vulnerabilities.