CVE-2021-39873 : Security Advisory and Response
Learn about CVE-2021-39873, a content spoofing vulnerability in GitLab CE/EE versions, allowing attackers to manipulate error responses and deceive users. Find mitigation steps and prevention measures.
In all versions of GitLab CE/EE, there exists a content spoofing vulnerability that attackers may exploit to trick users into visiting malicious websites.
Understanding CVE-2021-39873
In this section, we will explore the details of CVE-2021-39873.
What is CVE-2021-39873?
CVE-2021-39873 is a content spoofing vulnerability present in all versions of GitLab CE/EE. Attackers can leverage this vulnerability to deceive users into accessing malicious websites by spoofing content in error responses.
The Impact of CVE-2021-39873
The vulnerability has the following impact:
- CVSS Base Score: 4.3 (Medium)
- Attack Vector: Network
- User Interaction: Required
- Confidentiality Impact: Low
- Integrity Impact: None
- Privileges Required: None
- Scope: Unchanged
- Attack Complexity: Low
- Availability Impact: None
Technical Details of CVE-2021-39873
In this section, we will delve into the technical aspects of CVE-2021-39873.
Vulnerability Description
The vulnerability entails insufficient verification of data authenticity in GitLab, leading to content spoofing.
Affected Systems and Versions
The following versions of GitLab are affected:
- GitLab >=1.0, <14.1.7
- GitLab >=14.2, <14.2.5
- GitLab >=14.3, <14.3.1
Exploitation Mechanism
Attackers can exploit this vulnerability by manipulating error responses to display misleading content and trick users into visiting malicious sites.
Mitigation and Prevention
Let's explore the mitigation strategies for CVE-2021-39873.
Immediate Steps to Take
- Update GitLab to version 14.1.7, 14.2.5, or 14.3.1 to eliminate the vulnerability.
- Educate users about the risks of visiting untrusted websites.
Long-Term Security Practices
- Conduct regular security training sessions for developers to enhance awareness of content spoofing vulnerabilities.
- Implement strict data authenticity verification measures within GitLab to prevent similar exploits.
Patching and Updates
Regularly monitor GitLab security advisories and apply patches promptly to address known vulnerabilities.