CVE-2021-21244 : Exploit Details and Defense Strategies

OneDev, an all-in-one DevOps platform developed by TheOneDev, was found to have a critical vulnerability, CVE-2021-21244. This vulnerability, identified as 'Pre-Auth SSTI via Bean validation message tampering,' affects versions prior to 4.0.3. The issue allowed for pre-auth server-side template injection through Bean validation message tampering, posing a significant risk to confidentiality and integrity.

Understanding CVE-2021-21244

In this section, we will delve into the details of CVE-2021-21244 to understand the nature and implications of the vulnerability.

What is CVE-2021-21244?

The vulnerability in OneDev, CVE-2021-21244, enabled attackers to conduct pre-auth server-side template injection via tampering with Bean validation messages.

The Impact of CVE-2021-21244

CVE-2021-21244 has a critical severity level with a CVSS base score of 10, indicating a high impact on confidentiality and integrity. The vulnerability required no privileges for exploitation and had a low attack complexity.

Technical Details of CVE-2021-21244

Let's explore the technical aspects of CVE-2021-21244 to better comprehend the affected systems, exploitation mechanism, and available fixes.

Vulnerability Description

The vulnerability allowed threat actors to perform pre-auth server-side template injection by manipulating Bean validation messages in OneDev versions prior to 4.0.3.

Affected Systems and Versions

OneDev versions earlier than 4.0.3 are susceptible to CVE-2021-21244. Users of these versions are advised to update to the latest version to mitigate the risk.

Exploitation Mechanism

Attackers can exploit this vulnerability remotely via the network without requiring any special user interaction, making it a critical threat to the security of OneDev instances.

Mitigation and Prevention

To safeguard your systems and data from CVE-2021-21244, immediate action is necessary. Follow these steps to mitigate the risk and prevent potential exploitation.

Immediate Steps to Take

Upgrade OneDev to version 4.0.3 or higher to patch the vulnerability completely.
Monitor for any unusual activities or unauthorized access attempts in the system log.

Long-Term Security Practices

Regularly apply software updates and security patches to ensure the system's resilience against emerging threats.
Conduct periodic security assessments and audits to identify and address vulnerabilities proactively.

Patching and Updates

Stay informed about security advisories and updates from TheOneDev to protect your infrastructure from known vulnerabilities and security risks.