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 Cisco Universal Broadband Routers performing IPv6 VPN over Multiprotocol Label Switching (MPLS; 6VPE) and configured for NetFlow could allow an unauthenticated, remote attacker to cause a crash of the Parallel Express Forwarding (PXF) process on the Performance Routing Engine (PRE) module.
The vulnerability is due to a race condition that may cause an incorrect pointer to be used during IPv6 deaggregation. An attacker would need to control a trusted MPLS neighbor that can forward a malformed 6VPE packet at a high rate to an affected device. Successful exploitation could cause the PXF process on the PXE module of a targeted device to crash, resulting in a denial of service (DoS) condition
Cisco has confirmed the vulnerability and released software updates.
To exploit this vulnerability, the attacker must take control of a trusted MPLS neighbor that can forward a malformed 6VPE packet at a high rate to the targeted device, making exploitation more difficult in environments that restrict network access from untrusted sources.
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 CSCud83396 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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