TippingPoint Zero Day Initiative

Mozilla Firefox CSS font-face Remote Code Execution Vulnerability

ZDI-10-133: July 20th, 2010


CVSS Score

Affected Vendors

Affected Products

TippingPoint™ IPS Customer Protection

TippingPoint IPS customers are protected against this vulnerability by Digital Vaccine protection filter ID 10024. For further product information on the TippingPoint IPS:

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Mozilla Firefox. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within handling of references to external font resources. A value is used as a 16 bit integer in an array allocation and later as 32 bit when iterating over and then populating these fields. By creating enough references, a remote attacker can exploit this vulnerability to execute arbitrary code under the context of the browser.

Vendor Response

Mozilla Firefox has issued an update to correct this vulnerability. More details can be found at:

Disclosure Timeline

    2010-06-23 - Vulnerability reported to vendor
    2010-07-20 - Coordinated public release of advisory


This vulnerability was discovered by:
    J23 (http://twitter.com/HansJ23)