CVE-2021-43206 Explained : Impact and Mitigation

A server-generated error message in Fortinet FortiOS and FortiProxy versions allows malicious webservers to disclose sensitive information.

Understanding CVE-2021-43206

What is CVE-2021-43206?

A vulnerability in Fortinet FortiOS and FortiProxy enables attackers to extract a web proxy's client username and IP through specific HTTP requests.

The Impact of CVE-2021-43206

The vulnerability can lead to information disclosure by malicious webservers, compromising user privacy and security.

Technical Details of CVE-2021-43206

Vulnerability Description

The issue involves a server-generated error message in multiple versions of Fortinet FortiOS and FortiProxy that expose sensitive data to attackers.

Affected Systems and Versions

Fortinet FortiOS versions 7.0.0 to 7.0.3, 6.4.0 to 6.4.8, 6.2.x, 6.0.x
FortiProxy versions 7.0.0 to 7.0.1, 2.0.x

Exploitation Mechanism

Malicious webservers can exploit this vulnerability by triggering specific HTTP status codes pages through same-origin requests.

Mitigation and Prevention

Immediate Steps to Take

Monitor vendor updates for patches and security advisories.
Implement strict access controls and firewall rules to limit exposure.

Long-Term Security Practices

Conduct regular security assessments and penetration testing.
Train personnel on identifying and responding to security threats.

Patching and Updates

Ensure timely application of security patches provided by Fortinet to remediate the vulnerability.