Rule Category

BROWSER-FIREFOX -- Snort has detected traffic known to exploit vulnerabilities present in the Firefox browser, or products that have the "Gecko" engine (Thunderbird email client, etc.).

Alert Message

BROWSER-FIREFOX Mozilla Firefox potential use after free attempt

Rule Explanation

This rule will alert on potential attempts to exploit a use after free in Mozilla Firefox's JavaScript engine. Specifically, it will look for the manipulation of vulnerable "ContentViewer", "nsDocShell", and "ReadableStream" objects that if exploited successfully can lead to use after free conditions.

What To Look For

This rule fires on potential attempts to exploit a use after free vulnerability in Mozilla Firefox.

Known Usage

No public information

False Positives

No known false positives


Cisco Talos Intelligence Group

MITRE ATT&CK Framework

Tactic: Initial Access

Technique: Drive-by Compromise

For reference, see the MITRE ATT&CK vulnerability types here:

Additional Links

Rule Vulnerability

CVE Additional Information