Cisco Security Advisory
Cisco Unified IP Phones 9900 Series Denial of Service Vulnerability
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AV:N/AC:M/Au:N/C:N/I:N/A:P/E:F/RL:OF/RC:C
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A vulnerability in the packet storing capabilities of Cisco 9900 Series IP Phones could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
The vulnerability is due to how the phone decoder handles certain real-time transport protocol (RTP) packets. An attacker could exploit this vulnerability by calling a registered phone, waiting for a user to answer, then send malformed RTP packets to the user’s phone. A successful exploit could cause the phone to become unresponsive, resulting in a DoS condition.
Cisco has confirmed the vulnerability and released software updates.
To exploit this vulnerability, an attacker must first call a targeted phone and then rely on a user to answer the phone prior to sending malformed RTP packets. The attacker can not exploit this vulnerability without this requirement.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
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Cisco has released bug ID CSCur39976 for registered users, which contains additional details and an up-to-date list of affected product versions.
Vulnerable Products
At the time this alert was first published, Cisco Unified IP Phones 9900 Series release 9.3(2) was vulnerable. Later releases of Cisco Unified IP Phones 9900 Series may also be vulnerable.Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by these vulnerabilities.
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Administrators are advised to apply the appropriate updates.
Administrators are advised to monitor affected systems.
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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 email 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 2015-Jun-29
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