CVE-2019-20924 : Exploit Details and Defense Strategies

An individual with authorized access to perform database queries can cause denial of service in MongoDB Server v4.2 versions prior to 4.2.2 by executing carefully crafted queries that trigger a specific condition in the IndexBoundsBuilder.

Understanding CVE-2019-20924

This CVE involves an invariant in IndexBoundsBuilder in MongoDB Server versions.

What is CVE-2019-20924?

CVE-2019-20924 allows an authorized user to execute queries that lead to denial of service due to a vulnerability in MongoDB Server versions before 4.2.2.

The Impact of CVE-2019-20924

The vulnerability has a CVSS base score of 6.5, with a medium severity rating. It can result in a high impact on availability.

Technical Details of CVE-2019-20924

This section provides more technical insights into the CVE.

Vulnerability Description

The vulnerability arises from an invariant in the IndexBoundsBuilder, allowing authorized users to trigger denial of service through specially crafted queries.

Affected Systems and Versions

Product: MongoDB Server
Vendor: MongoDB Inc.
Versions Affected: MongoDB Server v4.2 versions prior to 4.2.2

Exploitation Mechanism

Attack Complexity: Low
Attack Vector: Network
Privileges Required: Low
Availability Impact: High
Scope: Unchanged
Vector String: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Mitigation and Prevention

Protecting systems from CVE-2019-20924 is crucial to maintaining security.

Immediate Steps to Take

Update MongoDB Server to version 4.2.2 or newer to mitigate the vulnerability.
Monitor and restrict database query permissions to authorized personnel.

Long-Term Security Practices

Regularly review and update access controls and permissions within the database.
Conduct security training for database administrators to recognize and prevent potential vulnerabilities.

Patching and Updates

Stay informed about security patches and updates released by MongoDB Inc.
Implement a robust patch management process to promptly apply necessary updates.