Cisco Security Advisory
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AV:N/AC:L/Au:N/C:N/I:N/A:P/E:F/RL:OF/RC:C
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A vulnerability in the DHCP version 6 (DHCPv6) code of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a hang condition of the DHCPv6 server process that could cause the software to stop processing DHCPv6 requests.
The vulnerability is due to incorrect handling of malformed DHCPv6 packets. An attacker could exploit this vulnerability by sending a malformed DHCPv6 packet to an affected device configured with DHCPv6 server functionality. An exploit could allow the attacker to cause a hang condition of the DHCPv6 server process that could cause the software to stop processing any further DHCPv6 requests.
Cisco has confirmed the vulnerability in a security notice and released software updates.
To exploit this vulnerability, an attacker may need access to trusted, internal networks to send malformed DCHPv6 packets to a targeted device. In addition, the device must be configured with DCHPv6 server functionality. These requirements may reduce the possibility of a successful exploit.
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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Customers are advised to consult Cisco bug ID CSCul80924 for a complete 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.
It is critical to prevent unauthorized direct communication to network devices. Restrict network traffic destined for the network infrastructure to protect against reconnaissance and denial of service attacks. For configuration details, see Protecting Your Core: Infrastructure Protection Access Control Lists.
Administrators are advised to monitor network traffic for security-related network activity. Cisco NetFlow can identify such activity. For more information about Cisco NetFlow, see Introduction to Cisco IOS NetFlow - A Technical Overview.
Administrators are advised to monitor affected systems.
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Cisco customers with active contracts should contact their Cisco support team for assistance in upgrading to a software version that includes fixes for this vulnerability. Cisco customers without contracts may contact the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at tac@cisco.com for assistance.
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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 2014-May-20
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