cisco-sa-phone-dos-txMYNRzv: Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of Service Vulnerability
A vulnerability in Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 that are running Cisco Session Initiation Protocol (SIP) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.This vulnerability is due to improper memory management when an affected device processes HTTP packets. An attacker could exploit this vulnerability by sending a continuous stream of crafted HTTP packets to the device. A successful exploit could allow the attacker to cause the affected device to continuously consume memory, resulting in a DoS condition. A manual reboot of the device is required to recover from this condition.Note: For this vulnerability to be exploitable, the phone must be registered to Cisco Unified Communications Manager (Unified CM) and have Web Access enabled. Web Access is disabled by default.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-phone-dos-txMYNRzv
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Ensure the phone is not exposed with Web Access enabled; Web Access is disabled by default (the vulnerability requires the phone to have Web Access enabled and be registered to Unified CM).
Cisco Unified Communications Manager (Unified CM) / Cisco phones Web Access = disabled
Event History
Frequently Asked Questions
Which devices are exposed to this denial-of-service issue?
Affected Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 devices are exposed only when running Cisco SIP Software, registered to Cisco Unified Communications Manager, and configured with Web Access enabled. Web Access is disabled by default.
What does an attacker need to exploit the vulnerability?
An unauthenticated remote attacker must be able to send a continuous stream of crafted HTTP packets to the affected phone. Successful exploitation causes ongoing memory consumption and a denial-of-service condition.
How can I recover an affected phone and mitigate the issue before updating?
A manual reboot is required to recover a device once it enters the denial-of-service condition. Cisco states that there are no workarounds; software updates are the available remediation.