Advisory Details

April 17th, 2006

Mozilla Firefox CSS Letter-Spacing Heap Overflow Vulnerability

ZDI-06-010
ZDI-CAN-015

CVE ID CVE-2006-1730
CVSS SCORE
AFFECTED VENDORS Mozilla Firefox
AFFECTED PRODUCTS 1.5.x
TREND MICRO CUSTOMER PROTECTION Trend Micro TippingPoint IPS customers are protected against this vulnerability by Digital Vaccine protection filter ID 4097. For further product information on the TippingPoint IPS: http://www.tippingpoint.com
VULNERABILITY DETAILS

This vulnerability allows attackers to execute arbitrary code on vulnerable installations of the Mozilla/Firefox web browser and Thunderbird e-mail client. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious e-mail.

The specific flaw is due to incorrect handling of the CSS "letter-spacing" element. By specifying a large number, an attacker can overflow an integer used during memory allocation. The under-allocated buffer is later used to store user-supplied data leading to an exploitable heap overflow.

ADDITIONAL DETAILS Mozilla Firefox has issued an update to correct this vulnerability. More details can be found at:
http://www.mozilla.org/security/announce/2006/mfsa2006-22.html
DISCLOSURE TIMELINE
  • 2006-01-31 - Vulnerability reported to vendor
  • 2006-04-17 - Coordinated public release of advisory
CREDIT Anonymous
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