CVE-2021-41823 : Security Advisory and Response

The Web Application Firewall (WAF) in Kemp LoadMaster 7.2.54.1 allows certain uses of onmouseover to bypass an XSS protection mechanism.

Understanding CVE-2021-41823

This CVE pertains to a vulnerability in the Kemp LoadMaster product that can be exploited to bypass XSS protection.

What is CVE-2021-41823?

The vulnerability allows specific onmouseover actions to circumvent the XSS protection mechanism in the Kemp LoadMaster 7.2.54.1.

The Impact of CVE-2021-41823

This vulnerability could be exploited by attackers to execute cross-site scripting attacks, potentially leading to unauthorized access or data theft.

Technical Details of CVE-2021-41823

The following are technical aspects of the CVE.

Vulnerability Description

The issue lies in how the WAF in Kemp LoadMaster handles onmouseover actions, allowing malicious actors to work around the XSS protection.

Affected Systems and Versions

Vendor: n/a
Product: n/a
Versions Affected: 7.2.54.1 (all versions affected)

Exploitation Mechanism

Attackers can utilize specific onmouseover techniques to trigger the vulnerability and execute XSS attacks.

Mitigation and Prevention

Steps to address and prevent the exploitation of CVE-2021-41823.

Immediate Steps to Take

Disable onmouseover events in web applications where possible.
Implement strict input validation to mitigate XSS risks.

Long-Term Security Practices

Keep WAF and related security measures updated.
Conduct regular security audits to identify and address vulnerabilities.

Patching and Updates

Apply patches and updates provided by Kemp for LoadMaster to fix this vulnerability.