Heap-based buffer overflow in the ISS Protocol Analysis Module (PAM), as used in certain versions of RealSecure Network 7.0 and Server Sensor 7.0, Proventia A, G, and M Series, RealSecure Desktop 7.0 and 3.6, RealSecure Guard 3.6, RealSecure Sentry 3.6, BlackICE PC Protection 3.6, and BlackICE Server Protection 3.6, allows remote attackers to execute arbitrary code via an SMB packet containing an authentication request with a long username.