Cisco Security Advisory
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AV:N/AC:H/Au:N/C:N/I:N/A:C/E:F/RL:OF/RC:C
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A vulnerability in the IPv6 to IPv4 subsystem of Cisco IOS Software could allow an unauthenticated, remote attacker to trigger a Performance Routing Engine (PRE) crash on a targeted system, resulting in a denial of service (DoS) condition.
The vulnerability is due to a race condition that may cause a NULL pointer to be freed. An attacker could exploit this vulnerability by submitting crafted content to a targeted device designed to trigger a race condition. A successful exploit could cause a PRE module on the device to crash, resulting in a DoS condition.
Cisco has confirmed the vulnerability and released software updates.
An attacker would need to cause hundreds of IPv6-enabled customer premises equipment (CPE) devices to drop and reestablish connectivity with the affected UBR simultaneously and repeatedly over a period of time. This requirement would make it difficult to achieve a successful exploit.
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Cisco has released bug ID CSCug47366 for registered users, which contains additional details and an up-to-date list of affected product versions.
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Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators can help protect affected systems from external attacks by using a solid firewall strategy.
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.
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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-22
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