Various Intrusion Detection Systems (IDS) including (1) Cisco Secure Intrusion Detection System, (2) Cisco Catalyst 6000 Intrusion Detection System Module, (3) Dragon Sensor 4.x, (4) Snort before 1.8.1, (5) ISS RealSecure Network Sensor 5.x and 6.x before XPU 3.2, and (6) ISS RealSecure Server Sensor 5.5 and 6.0 for Windows, allow remote attackers to evade detection of HTTP attacks via non-standard "%u" Unicode encoding of ASCII characters in the requested URL.

Multiple stack-based buffer overflows in the ICQ parsing routines of the ISS Protocol Analysis Module (PAM) component, as used in various RealSecure, Proventia, and BlackICE products, allow remote attackers to execute arbitrary code via a SRV_MULTI response containing a SRV_USER_ONLINE response packet and a SRV_META_USER response packet with long (1) nickname, (2) firstname, (3) lastname, or (4) email address fields, as exploited by the Witty worm.