Microsoft is currently investigating reports of a vulnerability in the Windows Server Message Block (SMB) protocol, for which a researcher posted exploit code last Monday. The vulnerability is in the mrxsmb.sys driver, and could be used to launch a denial of service attack or take control of the targeted system. Secunia ranked the vulnerability as "moderately critical." Vupen reported that Windows XP SP3 and Windows Server 2003 SP2 are both vulnerable, and other versions of Windows might also be affected.
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