CVE-2017-7803 : Security Advisory and Response

CVE-2017-7803 is a vulnerability affecting Thunderbird, Firefox ESR, and Firefox versions prior to specified numbers. The issue arises from the incorrect enforcement of Content Security Policy (CSP) due to the presence of a 'sandbox' directive in the header.

Understanding CVE-2017-7803

This CVE impacts various Mozilla products due to CSP misapplication.

What is CVE-2017-7803?

When a page's CSP header contains a 'sandbox' directive, other directives are not properly enforced, leading to CSP misapplication.

The Impact of CVE-2017-7803

The vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55, potentially allowing attackers to bypass security controls.

Technical Details of CVE-2017-7803

This section provides in-depth technical insights into the vulnerability.

Vulnerability Description

The presence of a 'sandbox' directive in a page's CSP header causes the incorrect enforcement of other directives, compromising CSP implementation.

Affected Systems and Versions

Thunderbird versions earlier than 52.3
Firefox ESR versions earlier than 52.3
Firefox versions earlier than 55

Exploitation Mechanism

Attackers can exploit this vulnerability to bypass CSP protections by leveraging the misapplied 'sandbox' directive.

Mitigation and Prevention

Protecting systems from CVE-2017-7803 requires immediate actions and long-term security measures.

Immediate Steps to Take

Update affected products to versions 52.3 for Thunderbird and Firefox ESR, and version 55 for Firefox.
Disable 'sandbox' directives in CSP headers where unnecessary.

Long-Term Security Practices

Regularly monitor and update CSP configurations.
Implement strict CSP policies to mitigate future vulnerabilities.

Patching and Updates

Apply security patches provided by Mozilla promptly to address the vulnerability and enhance system security.