Vulnerability Note VU#791496
Mozilla Firefox SVG animation nsSMILTimeContainer use-after-free vulnerability
Original Release date: 30 Nov 2016 | Last revised: 02 Dec 2016

Overview
Mozilla Firefox contains a use-after-free vulnerability in the SVG animation functionality, which may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

Description
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.

Impact
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.

Solution
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

Vendor Information (Learn More)

VendorStatusDate NotifiedDate UpdatedMozillaAffected-30 Nov 2016
TorAffected-30 Nov 2016If you are a vendor and your product is affected, let
us know.

CVSS Metrics (Learn More)

Group
Score
Vector

Base
7.5
AV:N/AC:L/Au:N/C:P/I:P/A:P

Temporal
6.5
E:H/RL:OF/RC:C

Environmental
6.5
CDP:ND/TD:H/CR:ND/IR:ND/AR:ND

References

https://www.mozilla.org/en-US/security/advisories/mfsa2016-92/
https://hg.mozilla.org/mozilla-central/rev/adcc39e3cad0
https://bugzilla.mozilla.org/show_bug.cgi?id=1321066
https://blog.gdatasoftware.com/2016/11/29346-firefox-0-day-targeting-tor-users
http://support.microsoft.com/kb/2458544

Credit
This document was written by Will Dormann.

Other Information

CVE IDs:
CVE-2016-9079

Date Public:
29 Nov 2016

Date First Published:
30 Nov 2016

Date Last Updated:
02 Dec 2016

Document Revision:
14

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