CVE-2020-35111 Explained : Impact and Mitigation

A vulnerability in Firefox, Thunderbird, and Firefox ESR versions prior to specified versions could lead to IP address leakage when viewing source URLs.

Understanding CVE-2020-35111

This CVE highlights a flaw in the proxy.onRequest API that fails to handle view-source URLs properly, potentially exposing users' IP addresses.

What is CVE-2020-35111?

When certain extensions with specific permissions are used, the proxy.onRequest callback may not trigger for view-source URLs, posing a risk of unintentional IP address exposure.

The Impact of CVE-2020-35111

The vulnerability could allow malicious actors to obtain users' IP addresses by exploiting the flaw in handling view-source URLs.

Technical Details of CVE-2020-35111

This section provides detailed technical insights into the vulnerability.

Vulnerability Description

The issue arises from the proxy.onRequest API failing to intercept view-source URLs, potentially leading to IP address exposure.

Affected Systems and Versions

Firefox versions prior to 84
Thunderbird versions prior to 78.6
Firefox ESR versions prior to 78.6

Exploitation Mechanism

By leveraging the flaw in handling view-source URLs, attackers could craft scenarios to extract users' IP addresses.

Mitigation and Prevention

Protecting systems from CVE-2020-35111 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update affected applications to versions equal to or above the specified fixed versions.
Avoid opening view-source URLs from untrusted sources.

Long-Term Security Practices

Regularly update software and extensions to mitigate potential vulnerabilities.
Educate users on safe browsing practices to minimize risks.

Patching and Updates

Apply patches provided by Mozilla for Firefox, Thunderbird, and Firefox ESR to address the vulnerability.