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 Cisco Express Forwarding processing module that checks the sanity of IP headers on Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, leading to a denial of service (DoS) condition.
The vulnerability is due to improper processing of Multiprotocol Label Switching (MPLS) packets. When certain additional features are configured, an attacker could exploit this vulnerability by sending MPLS packets to traverse and exit an affected device as IP packets. An exploit could allow the attacker to cause the device to reload, leading to a DoS condition.
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; in which the targeted device may reside, in order to send MPLS packets. This access requirement may reduce the likelihood 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 CSCuj23992 for a complete list of affected product versions.Vulnerable Products
At the time this alert was first published, Cisco IOS XE Software Releases 3.9S(.1) and prior were vulnerable. Later releases of Cisco IOS XE Software may also be vulnerable.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 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 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 2013-Dec-02
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