CVE-2021-23968 : Security Advisory and Response

A security vulnerability in Mozilla Firefox, Thunderbird, and Firefox ESR could lead to sensitive information leakage due to improper handling of frame navigation.

Understanding CVE-2021-23968

This CVE identifier refers to a flaw in how the Content Security Policy handles frame navigation and redirects in Mozilla products.

What is CVE-2021-23968?

If the Content Security Policy blocked frame navigation, the full destination of a redirect served in the frame was disclosed in the violation report instead of the original frame URI. This issue could be exploited to expose sensitive information present in the redirected URLs across Firefox, Thunderbird, and Firefox ESR versions prior to specific versions.

The Impact of CVE-2021-23968

This vulnerability could potentially allow attackers to access and exploit sensitive information contained in the redirect URLs, leading to privacy breaches and data leakage.

Technical Details of CVE-2021-23968

The vulnerability stems from the improper reporting of redirect destinations in violation reports, enabling the disclosure of sensitive information within redirect URLs.

Vulnerability Description

The flaw allowed the full destination of a redirect served in the frame to be disclosed in the violation report, potentially exposing sensitive data.

Affected Systems and Versions

Mozilla Firefox versions prior to < 86, Thunderbird versions before < 78.8, and Firefox ESR versions lower than < 78.8 are impacted by this vulnerability.

Exploitation Mechanism

By leveraging the mishandling of frame navigation, malicious actors could exploit this vulnerability to extract confidential information from the disclosed redirect destinations.

Mitigation and Prevention

To safeguard systems from potential exploitation of CVE-2021-23968, immediate action and long-term security measures are recommended.

Immediate Steps to Take

Users are advised to update their Mozilla Firefox, Thunderbird, and Firefox ESR to versions 86, 78.8, and 78.8 respectively to mitigate the vulnerability. Additionally, monitoring and restricting network traffic can help minimize the risk of exposure.

Long-Term Security Practices

Implementing strict Content Security Policies, regular security audits, and user awareness training can enhance overall security posture and help prevent similar vulnerabilities in the future.

Patching and Updates

Stay informed about security updates and patches released by Mozilla for Firefox, Thunderbird, and Firefox ESR to address known vulnerabilities and protect systems from exploitation.