Cisco 9900 Series IP phones contain a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
A vulnerability in Session Initiation Protocol (SIP) header processing of Cisco fourth-generation IP phones could allow an unauthenticated, remote attacker to cause the IP phone to unregister.
The vulnerability is due to improper SIP header processing. An attacker could exploit this vulnerability by sending a crafted SIP header to the affected phone. An exploit could allow the attacker to force the IP phone to unregister.
Cisco has confirmed the vulnerability in a security notice and released software updates.
At the time this alert was first published, Cisco Unified IP Phones 9900 Series Firmware versions 9.3(.4) and prior were vulnerable. Later releases may also be vulnerable.
To exploit this vulnerability, it is likely that an attacker would need access to trusted, internal networks to send a crafted SIP header to a targeted phone. This access requirement may reduce the likelihood of a successful attack.
Cisco has released a security notice at the following link: CVE-2013-0658
Customers are advised to consult Cisco bug ID CSCul24898 for a complete list of affected product versions.
An unauthenticated, remote attacker could exploit this vulnerability to cause an affected device to unregister, resulting in a denial of service (DoS) condition.
The vulnerability is due to improper SIP header processing by Cisco 9900 Series IP phones.
An unauthenticated, remote attacker could exploit this vulnerability by sending a crafted SIP header to the affected phone. An exploit could allow the attacker to force the IP phone to unregister, resulting in a DoS condition.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor affected systems.
Cisco customers with active contracts should contact their Cisco support team for assistance in upgrading to a software version that includes fixes for this vulnerability. Cisco customers without contracts may contact the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at firstname.lastname@example.org for assistance.
The security vulnerability applies to the following combinations of products.
Cisco Unified IP Phones 9900 Series Firmware
9.3 Base, .1, .2, .2 SR1, .4
The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.