CVE-2021-20330 : What You Need to Know

A detailed overview of CVE-2021-20330, a vulnerability impacting MongoDB Server versions prior to 4.0.27, 4.2.16, and 4.4.9, potentially leading to denial of service attacks on secondaries.

Understanding CVE-2021-20330

This section provides insights into the impact, technical details, and mitigation strategies related to CVE-2021-20330.

What is CVE-2021-20330?

CVE-2021-20330 is a vulnerability that allows an attacker with basic CRUD permissions on a replicated collection to exploit specially malformed oplog entries through the applyOps command. This can result in a potential denial of service on MongoDB Server secondaries.

The Impact of CVE-2021-20330

The vulnerability affects MongoDB Server versions including 4.0.27, 4.2.16, and 4.4.9. Attackers can execute specific replication commands to crash MongoDB Server secondaries, impacting availability.

Technical Details of CVE-2021-20330

This section delves into the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

An attacker can leverage malformed oplog entries in a replicated collection, leading to denial of service attacks on MongoDB Server secondaries.

Affected Systems and Versions

MongoDB Server versions prior to 4.0.25, 4.2.14, and 4.4.6 are vulnerable to CVE-2021-20330, specifically versions 4.0, 4.2, and 4.4.

Exploitation Mechanism

The vulnerability can be exploited by executing applyOps command with specially crafted oplog entries to crash MongoDB Server secondaries.

Mitigation and Prevention

Explore immediate steps and long-term security practices to mitigate the risks associated with CVE-2021-20330.

Immediate Steps to Take

Administrators should update MongoDB Server to patched versions, such as 4.0.27, 4.2.16, and 4.4.9, to address the vulnerability immediately.

Long-Term Security Practices

Implement proper input validation procedures, restrict access permissions, and monitor replication commands to enhance the security posture.

Patching and Updates

Regularly apply security patches released by MongoDB Inc. to protect systems from known vulnerabilities.