CVE-2021-39914 : Exploit Details and Defense Strategies

GitLab has identified a regular expression denial of service vulnerability in specific versions, potentially leading to resource exhaustion when provisioning new users.

Understanding CVE-2021-39914

This CVE details the impact of a denial of service vulnerability in GitLab versions.

What is CVE-2021-39914?

This vulnerability in GitLab versions 8.13 to 14.2.5, 14.3.0 to 14.3.3, and 14.4.0 involves a regular expression denial of service issue that could heavily consume resources if a malicious username is used during user provisioning.

The Impact of CVE-2021-39914

The identified vulnerability has a CVSS base score of 3.1 (Low severity) with a HIGH attack complexity and a NETWORK attack vector. It could lead to excessive resource usage.

Technical Details of CVE-2021-39914

Explore the technical aspects of this vulnerability in GitLab.

Vulnerability Description

The vulnerability allows for uncontrolled resource consumption when a specially crafted username triggers the regex denial of service in affected GitLab versions.

Affected Systems and Versions

Affected versions: >=8.13, <14.2.6, >=14.3.0, <14.3.4, >=14.4.0, <14.4.1

Exploitation Mechanism

The issue arises when provisioning new users with specifically designed usernames, triggering the irregular consumption of resources.

Mitigation and Prevention

Discover the steps to mitigate and prevent potential exploitation.

Immediate Steps to Take

Users should update to GitLab versions 14.2.6, 14.3.4, or 14.4.1 to eliminate the vulnerability.
Avoid provisioning users with suspicious or crafted usernames to reduce the risk.

Long-Term Security Practices

Regularly monitor and update GitLab to ensure the latest security patches are applied.
Educate users and administrators on secure username practices to prevent similar future issues.

Patching and Updates

GitLab users are advised to apply the latest patches provided by GitLab to address this vulnerability.