Microsoft has posted a security bulletin for the Unchecked Buffer in Gopher Protocol Handler Can Run Code of Attacker's Choice problem

This is a work-around bulletin that details steps customers can take to protect themselves against a publicly disclosed vulnerability until patches are available.

The Gopher protocol is a legacy protocol that provides for the transfer of text-based information across the Internet. Information on Gopher servers is hierarchically presented using a menu system, and multiple Gopher servers can be linked together to form a collective Gopherspace.

There is an unchecked buffer in a piece of code which handles the response from Gopher servers. This code is used independently in IE, ISA, and Proxy Server. A security vulnerability results because it is possible for an attacker to attempt to exploit this flaw by mounting a buffer overrun attack through a specially crafted server response. The attacker could seek to exploit the vulnerability by crafting a web page that contacted a server under the attacker's control. The attacker could then either post this page on a web site or send it as an HTML email. When the page was displayed and the server's response received and processed, the attack would be carried out.

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