CVE-2021-22994 : Exploit Details and Defense Strategies

A reflected Cross-Site Scripting (XSS) vulnerability has been identified in BIG-IP versions 11.6.x to 16.0.x, posing a risk of system compromise. The issue resides in undisclosed endpoints of iControl REST, potentially leading to a complete compromise if the victim user holds admin privileges. This vulnerability was introduced due to an incomplete fix for CVE-2020-5948.

Understanding CVE-2021-22994

This section delves into the details of the CVE-2021-22994 vulnerability affecting BIG-IP systems.

What is CVE-2021-22994?

CVE-2021-22994 is a reflected XSS vulnerability in BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3, and 11.6.x before 11.6.5.3. It allows attackers to execute malicious scripts in a victim's browser, potentially leading to unauthorized access and data theft.

The Impact of CVE-2021-22994

The vulnerability exposes BIG-IP systems to the risk of a complete compromise if exploited by an attacker with admin privileges. By leveraging this flaw, malicious actors can inject and execute scripts within the context of the victim's session, posing a severe threat to system confidentiality and integrity.

Technical Details of CVE-2021-22994

This section outlines the technical aspects of the CVE-2021-22994 vulnerability in BIG-IP systems.

Vulnerability Description

The vulnerability stems from undisclosed endpoints in iControl REST, allowing for a reflected XSS attack. If an admin-level user interacts with a malicious script, it could result in a full system compromise.

Affected Systems and Versions

BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3, and 11.6.x before 11.6.5.3 are impacted by this vulnerability.

Exploitation Mechanism

The vulnerability allows attackers to craft a malicious URL containing a script that, when accessed by a victim with admin privileges, triggers the execution of the script within the victim's session.

Mitigation and Prevention

Learn how to protect your BIG-IP systems from CVE-2021-22994 and minimize the associated risks.

Immediate Steps to Take

It is recommended to apply security patches provided by F5 Networks promptly. Additionally, restrict admin privileges to trusted users to mitigate the risk of exploitation.

Long-Term Security Practices

Implement regular security training for users to recognize and avoid phishing attempts and malicious URLs. Conduct periodic vulnerability assessments and ensure timely patching of software.

Patching and Updates

Stay informed about the latest security advisories and updates from F5 Networks. Regularly monitor for CVE-2021-22994-related patches and apply them to ensure the security of your BIG-IP infrastructure.