The (1) Cisco Unified Communications Manager Express; (2) SIP Gateway Signaling Support Over Transport Layer Security (TLS) Transport; (3) Secure Signaling and Media Encryption; (4) Blocks Extensible Exchange Protocol (BEEP); (5) Network Admission Control HTTP Authentication Proxy; (6) Per-user URL Redirect for EAPoUDP, Dot1x, and MAC Authentication Bypass; (7) Distributed Director with HTTP Redirects; and (8) TCP DNS features in Cisco IOS 12.0 through 12.4 do not properly handle IP sockets, which allows remote attackers to cause a denial of service (outage or resource consumption) via a series of crafted TCP packets.