Microsoft Corp. on Tuesday released an updated patch for a known vulnerability in its MSN Chat control because the original fix didnt prevent the problem from recurring.
Although the original patch resolved the vulnerability, it failed to prevent the vulnerable ActiveX control from being reintroduced into the system, Microsoft said. As a result, the company has released a new patch, an updated version of the MSN Chat control and an updated version of MSN Messenger.
The revised bulletin and updated patch are available here.
The vulnerability lies in the MSN Chat control, which is an ActiveX control that ships with all three Microsoft instant messaging clients and is also available for download from several MSN sites. There is an unchecked buffer in one of the components that handles input parameters in the MSN Chat control, and an attacker could use this to launch a buffer overrun attack and run code in the context of the user.
To exploit the vulnerability, an attacker would either need to entice the user to open an HTML e-mail or visit a Web site containing the malicious code.
The Redmond, Wash., company on Tuesday also warned that an old protocol used for transferring text across the Internet can cause a critical vulnerability in Internet Explorer, Proxy Server and the Internet Security and Acceleration Server.
The Gopher protocol is a legacy protocol used to access and transfer hierarchically presented data among remote machines. An unchecked buffer in the code that handles responses from Gopher servers gives an attacker the ability to run arbitrary code on vulnerable machines.
To execute such an attack, the attacker would need to create a Web page that contacted a server under his control and either post it or send it as an HTML e-mail.
There is no patch available for this vulnerability, and news of the flaw has been circulating on security mailing lists for more than a week.
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