This attack could pose a serious security threat. You should take immediate action to stop any damage or prevent further damage from happening.
This signature detects an attempt to exploit a privilege escalation vulnerability in Firefox that may result in remote code execution.
Firefox is a browser. SeaMonkey is a suite of applications that includes a browser and an email client. Thunderbird is an email client. All three applications are available for multiple platforms.
Mozilla Firefox, SeaMonkey, and Thunderbird are prone to a privilege-escalation vulnerability because it is possible to open a chrome privileged web page through plugin objects through interaction with SVG elements.
An attacker can exploit this issue by enticing an unsuspecting user into viewing malicious content. A successful exploit will result in the execution of arbitrary attacker-supplied code with elevated privileges. Failed exploit attempts will likely result in denial-of-service conditions.