The Nortel UNIStim IP Softphone 2050, IP Phone 1140E, and additional Nortel products from the IP Phone, Business Communications Manager (BCM), Mobile Voice Client, and other product lines, allow remote attackers to block calls and force re-registration via a resume message to the Signaling Server that has a spoofed source IP address for the phone. NOTE: the attack is more disruptive if a new spoofed resume message is sent after each re-registration.

The Nortel UNIStim IP Softphone 2050, IP Phone 1140E, and additional Nortel products from the IP Phone, Business Communications Manager (BCM), and other product lines, use only 65536 different values in the 32-bit ID number field of an RUDP datagram, which makes it easier for remote attackers to guess the RUDP ID and spoof messages. NOTE: this can be leveraged for an eavesdropping attack by sending many Open Audio Stream messages.

The Nortel UNIStim IP Softphone 2050, IP Phone 1140E, and additional Nortel products from the IP Phone, Business Communications Manager (BCM), and other product lines allow remote attackers to eavesdrop on the physical environment via an Open Audio Stream message that enables "surveillance mode." NOTE: issues relating to a small ID number space can be leveraged to make this attack easier.

Multiple TCP implementations with Protection Against Wrapped Sequence Numbers (PAWS) with the timestamps option enabled allow remote attackers to cause a denial of service (connection loss) via a spoofed packet with a large timer value, which causes the host to discard later packets because they appear to be too old.

Multiple vulnerabilities in the H.323 protocol implementation for Nortel Networks Business Communications Manager (BCM), Succession 1000 IP Trunk and IP Peer Networking, and 802.11 Wireless IP Gateway allow remote attackers to cause a denial of service and possibly execute arbitrary code, as demonstrated by the NISCC/OUSPG PROTOS test suite for the H.225 protocol.