A vulnerability in the code handling the ISDN Q.931 signaling protocol of the Cisco TelePresence ISDN Gateway could allow an unauthenticated, remote attacker to trigger a drop of the data channel (D-channel), causing all calls to be terminated and preventing users from making new calls.
The vulnerability is due to improper handling of a crafted Q.931 STATUS message. An attacker could exploit this vulnerability by injecting crafted packets in the Q.931 flow. An successful exploit could allow the attacker to trigger a drop of the D-channel. As a result, all active calls handled by the affected system will be terminated and it will not be possible to establish new calls until the D-channel communication is restored. A software reload is necessary to restore normal behavior.
Cisco TelePresence ISDN Gateway contains a vulnerability that could allow an unauthenticated, remote attacker to trigger the drop of the data channel (D-channel), causing all calls to be terminated and preventing users from making new calls.
Cisco has released software updates that address this vulnerability. No workarounds that mitigate this vulnerability are available. This advisory is available at the following link: