Software Engineering Institute

Mozilla Firefox supports SVG animation through the use of SMIL. The nsSMILTimeContainer object contains a use-after-free vulnerability, which can allow arbitrary code execution.

Exploit code for this vulnerability is publicly available, which specifically targets the Tor Browser Bundle.

By convincing a use to view specially-crafted web content, a remote-unauthenticated attacker may be able to execute arbitrary code on an affected system.

Apply an update

This issue is addressed in Tor Browser 6.0.7 and Mozilla Firefox versions 50.0.2 and 45.5.1 ESR, as well as Thunderbird 45.5.1.

Disable JavaScript

This vulnerability can be mitigated by disabling JavaScript. This can be accomplished through use of the NoScript Firefox add-on.

Use the Microsoft Enhanced Mitigation Experience Toolkit

The Microsoft Enhanced Mitigation Experience Toolkit (EMET) can be used to help prevent exploitation of this and other vulnerabilities. Limited testing has shown that the following mitigations present in EMET 4.0 and later blog the public exploit for this vulnerability:

• StackPivot
• EAF
• Caller