Cisco Security Advisory
Cisco IOS Software Crafted IPv6 over MPLS Denial of Service Vulnerability
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AV:A/AC:L/Au:N/C:N/I:N/A:C/E:F/RL:OF/RC:C
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Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) on a targeted device.
The vulnerability is due to the processing of IP version 6 (IPv6) packets by the vulnerable version of software on an affected device. If an unauthenticated, remote attacker is able to access and send these packets to the vulnerable device, the device may reload, causing a DoS condition and disrupting normal operations.
Cisco has confirmed this vulnerability in a security advisory and has released updated software.
It is likely that an attacker would need to have access to an internal, private network--more specifically to an adjacent network--to send crafted packets to a vulnerable device. This requirement could limit the possibility for an attack.
In addition, a crafted packet used to exploit this vulnerability would be silently discarded if received on an interface if the packet did not have an MPLS label.
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 a security advisory for Cisco bug ID CSCto07919 at the following link: cisco-sa-20110928-ipv6mpls
Vulnerable Products
Cisco has published a list of affected Cisco IOS Software releases in the security advisory. The Vendor Announcements section of this alert contains a link to the advisory.
Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by these vulnerabilities.
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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 are advised to implement an intrusion prevention system (IPS) or intrusion detection system (IDS) to help detect and prevent attacks that attempt to exploit this vulnerability.
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 e-mail 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 2011-Sep-28
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