Microsoft Security Bulletin MS02-022 - Unchecked Buffer in MSN Chat Control Can Lead to Code Execution (Q321661)

[Newsbot]

Dieser Patch soll einen Fehler in der MSN Chat Control Software beseitigen. Der Patch ist zwar schon einige Tage alt, wurde aber am heutigen Tag erneut aktualisiert.

On May 8 2002, Microsoft released the original version of this bulletin. On June 11, 2002 the bulletin was updated to announce that while the fixes issued on May 8 2002 resolved the vulnerability, they did not protect in all cases against the reintroduction of the vulnerable control. As a result, a new set of fixes is being released to ensure that systems are fully protected against the reintroduction of the vulnerable control. A new MSN Chat control, updated patch, updated version of MSN Messenger and an updated version of Exchange Instant Messenger have been made available. Customers who have applied any of the fixes released on May 8, 2002 are encouraged to consider applying the updated fixes.

The MSN Chat control is an ActiveX control that allows groups of users to gather in a single, virtual location online to engage in text messaging. The control is offered for download as a single ActiveX control from a number of MSN sites. In addition, it is included with MSN Messenger since version 4.5 and Exchange Instant Messenger. While the MSN Chat control is included with these products it is not used to provide Instant Messaging functionality, but rather to add chat functionality to those products.

An unchecked buffer exists in one of the functions that handles input parameters in the MSN Chat control. A security vulnerability results because it is possible for a malicious user to levy a buffer overrun attack and attempt to exploit this flaw. A successful attack could allow code to run in the user's context.

It would be possible for an attacker to attempt to exploit this vulnerability either through a malicious web site or through HTML email. However, Outlook Express 6.0 and the Outlook Email Security Update, which is available for Outlook 98 and Outlook 2000, Outlook 2002 and can thwart such attempts through their default security settings.

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