CVE-2017-7791 Explained : Impact and Mitigation

A security vulnerability impacting Thunderbird, Firefox ESR, and Firefox versions prior to specified releases.

Understanding CVE-2017-7791

A vulnerability allowing the creation of modal alerts across different domains using the "data:" protocol.

What is CVE-2017-7791?

The flaw enables the display of deceptive modal alerts on webpages with iframes, falsely attributing them to the iframe content.

The Impact of CVE-2017-7791

Affected products: Thunderbird, Firefox ESR, Firefox
Versions impacted: Thunderbird < 52.3, Firefox ESR < 52.3, Firefox < 55

Technical Details of CVE-2017-7791

A vulnerability description affecting multiple Mozilla products.

Vulnerability Description

The usage of the "data:" protocol on webpages with iframes allows for the creation of deceptive modal alerts across domains.

Affected Systems and Versions

Thunderbird versions prior to 52.3
Firefox ESR versions prior to 52.3
Firefox versions prior to 55

Exploitation Mechanism

The flaw enables the display of modal alerts that appear to originate from iframe content, creating a false impression.

Mitigation and Prevention

Steps to address and prevent the CVE-2017-7791 vulnerability.

Immediate Steps to Take

Update Thunderbird, Firefox ESR, and Firefox to versions 52.3 and above
Exercise caution when interacting with modal alerts on webpages

Long-Term Security Practices

Regularly update browsers and email clients
Educate users on recognizing deceptive modal alerts

Patching and Updates

Apply patches provided by Mozilla for Thunderbird, Firefox ESR, and Firefox