Cisco Security Advisory
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AV:N/AC:L/Au:N/C:P/I:N/A:N/E:F/RL:OF/RC:C
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A vulnerability in the implementation of the access list logging feature of Cisco Nexus 9000 Series Switches could allow an unauthenticated, remote attacker to bypass the access list restriction for the logged traffic.
The vulnerability is due to insufficient policy checks for the logged packets. An attacker could exploit this vulnerability by sending a flood of denied packets that match an access list entry with the log keyword. An exploit could allow the attacker to bypass the access control list for a small percentage of the packets, which would otherwise have been dropped.
Cisco has confirmed the vulnerability in a security notice and released software updates.
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 CSCuo02489 for a complete list of affected product versions.
Vulnerable Products
At the time this alert was first published, Cisco Nexus 9000 Series Switches running Cisco NX-OS Software version 6.1(2)I2(1) is vulnerable. Later releases of Cisco NX-OS 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 can help protect affected systems from external attacks by using a solid firewall strategy.
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 may consider using the hardware rate limiter feature to drop all packets that are sent for logging purposes.
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-Aug-06
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