CVE-2014-0660

Vulnerability

The vulnerability exists in the ISDN Q.931 signaling protocol handling of the Cisco TelePresence ISDN Gateway. It allows an unauthenticated, remote attacker to trigger a drop of the D-channel by injecting a crafted Q.931 STATUS message into the signaling flow. Affected versions include all software releases prior to 2.2(1.92) running on Cisco TelePresence ISDN GW 3241 or Cisco TelePresence ISDN GW MSE 8321 [1].

Exploitation

An attacker can exploit the vulnerability by injecting specially crafted packets in the Q.931 flow. No authentication or prior access is required; the attacker only needs network access to the signaling path between the gateway and the ISDN network. Successful injection of the crafted STATUS message causes the D-channel to drop [1].

Impact

A successful exploit results in a denial-of-service condition where all active calls handled by the affected system are terminated. New calls cannot be established until the D-channel communication is restored, which requires a software reload of the gateway [1].

Mitigation

Cisco has released software update version 2.2(1.92) to address this vulnerability. No workarounds exist. All affected users should upgrade to the fixed release as soon as possible [1].