Cisco Security Advisory
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AV:R/AC:L/Au:NR/C:N/I:N/A:C/B:N/E:P/RL:O/RC:C
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Cisco 7940 and 7960 IP phones with firmware version 7.4 contain a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
The vulnerability exists due to an error within the handling of malformed SIP INVITE messages. An attacker could exploit this vulnerability by sending a crafted INVITE message to the device to cause it to reboot, resulting in a temporary DoS condition.
Proof-of-concept code is available.
Cisco confirmed this vulnerability and released updates to correct it.
To exploit this vulnerability, the attacker must have access to the network on which the device resides. Another attack vector would be a SIP gateway that could pass the malicious SIP INVITE message to an affected device. Typically IP phones reside on their own network, which could prevent an external attacker from exploiting this vulnerability. However, an attacker with physical access to an IP phone could potentially unplug the phone and access the phone network directly from the connection that the IP phone normally plugs into.
Cisco has released firmware version 8.6 is not affected by this vulnerability
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Cisco has released a security response at the following link: cisco-sr-20070320
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Administrators are advised to apply the appropriate updates.
Administrators are advised to place all Cisco IP phones on an isolated network or VLAN. This will help prevent outside attackers from being able to exploit this security issue.
Administrators are advised to maintain physical security on IP phone ports. Any unused ports should be disabled until needed.
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Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via e-mail at tac@cisco.com.
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The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Show LessVersion Description Section Status Date 1.0 Initial Release NA Final 2007-Mar-20
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