CVE-2018-12393 : Security Advisory and Response

A vulnerability was discovered in 32-bit versions of Firefox, Firefox ESR, and Thunderbird, potentially leading to an out-of-bounds write due to an integer overflow during Unicode conversion.

Understanding CVE-2018-12393

What is CVE-2018-12393?

The vulnerability arises from an excessive increase in value during script conversion to an internal UTF-16 format in 32-bit builds of Firefox, Firefox ESR, and Thunderbird.

The Impact of CVE-2018-12393

The vulnerability could allow malicious actors to trigger an out-of-bounds write, potentially leading to arbitrary code execution or system compromise.

Technical Details of CVE-2018-12393

Vulnerability Description

The issue occurs in 32-bit builds due to an integer overflow during Unicode conversion, causing a buffer allocated for conversion to become insufficient.

Affected Systems and Versions

Firefox versions prior to 63
Firefox ESR versions prior to 60.3
Thunderbird versions prior to 60.3

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting malicious scripts that trigger the integer overflow during Unicode conversion, leading to the out-of-bounds write.

Mitigation and Prevention

Immediate Steps to Take

Update affected software to versions 63 (or later) for Firefox, 60.3 (or later) for Firefox ESR, and 60.3 (or later) for Thunderbird.
Consider using 64-bit versions of the software to avoid this vulnerability.

Long-Term Security Practices

Regularly update software to the latest versions to patch known vulnerabilities.
Implement secure coding practices to prevent integer overflow vulnerabilities.

Patching and Updates

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