Vulnerability Note VU#316553

The Microsoft Windows kernel includes a driver (win32k.sys) that handles a variety of graphics processing tasks, including the processing of TrueType fonts. A vulnerability exists in the way this driver handles certain embedded TrueType fonts. This vulnerability could allow an attacker to execute code with elevated privileges on the affected system.

A remote attacker could exploit this vulnerability by embedding a specially crafted font in a document attached to an email message or including the crafted font in a web page.

An attacker may be able to run arbitrary code in kernel mode, resulting in complete system compromise. Secondary impacts include, but are not limited to, installation of programs; viewing, changing, or deleting data; or the creation of new system accounts with full privileges.

Apply an update

Microsoft has addressed this issue in Microsoft Security Bulletin MS11-087. Users may also wish to consider applying the following workaround:

Deny access to T2EMBED.DLL

Microsoft has published a workaround for this issue in Microsoft Security Advisory (2639658), which recommends denying access to T2EMBED.DLL. Users are encouraged to review this advisory and consider applying the workaround that it describes. Additionally, Microsoft Knowledge Base Article 2639658 contains Microsoft Fix it 50792 and Microsoft Fix it 50793 to help users apply this workaround.