Cisco Security Advisory
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CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:X/RL:X/RC:X
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A vulnerability in the implementation of Session Initiation Protocol (SIP) functionality in Cisco Small Business SPA51x Series IP Phones could allow an unauthenticated, remote attacker to cause an affected device to become unresponsive, resulting in a denial of service (DoS) condition.
The vulnerability is due to the improper handling of SIP request messages by an affected device. An attacker could exploit this vulnerability by sending malformed SIP messages to an affected device. A successful exploit could allow the attacker to cause the affected device to become unresponsive, resulting in a DoS condition that persists until the device is restarted manually.
Cisco has released firmware updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171018-sip
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Vulnerable Products
This vulnerability affects Cisco Small Business SPA51x Series IP Phones that are running Cisco SPA51x Firmware Release 7.6.2SR1 or earlier.Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect Cisco Small Business SPA50x Series IP Phones or Cisco Small Business SPA52x Series IP Phones.
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There are no workarounds that address this vulnerability.
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Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.htmlAdditionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC:
http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.htmlCustomers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
This vulnerability was fixed in Cisco SPA51x firmware releases 7.6.2SR2 and later for Cisco Small Business SPA51x Series IP Phones.
Customers should upgrade to the latest firmware release by visiting the Software Center on Cisco.com and navigating to Collaboration Endpoints > IP Phones Small Business SPA500 Series IP Phones > IP phone model > IP Telephone Firmware.
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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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This vulnerability was found during internal testing.
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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 public release. — Final 2017-October-18
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