Cisco NX-OS Software contains a vulnerability that could allow an unauthenticated, adjacent attacker to cause a denial of service condition. Updates are available.
A vulnerability in the IP version 6 (IPv6) packet handling routine of Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a device to stop responding to neighbor solicitation (NS) requests, causing a limited denial of service (DoS) condition.
The vulnerability is due to improper processing of adjacencies in the IPv6 neighbor table. An attacker could exploit this vulnerability by sending a sequence of malformed IPv6 packets to an affected device. An exploit could allow the attacker to cause a device to stop responding to NS requests, causing a limited DoS condition.
Cisco has confirmed the vulnerability in a security notice and released software updates.
At the time this alert was first published, Cisco NX-OS Software versions 4.1(2)E1(1j) and prior were vulnerable. Later releases of Cisco NX-OS Software may also be vulnerable.
To exploit this vulnerability, an attacker would need access to the same broadcast or collision domain of the targeted device. This access requirement decreases 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.
Cisco has released a security notice at the following link: CVE-2013-6683
Customers are advised to consult Cisco bug ID CSCtd15904 for the most complete list of affected product versions.
An unauthenticated, adjacent attacker could exploit this vulnerability to cause an affected device to stop responding to NS requests, resulting in a limited DoS condition.
The vulnerability is due to improper processing of adjacencies in the IPv6 neighbor table by Cisco Nexus 4000 Series Switches running an affected version of Cisco NX-OS Software.
An unauthenticated, adjacent attacker could exploit this vulnerability by sending a sequence of malformed IPv6 packets to an affected device. An exploit could allow the attacker to cause a device to stop responding to NS requests, causing a limited DoS condition.
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.
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 email@example.com for assistance.
The security vulnerability applies to the following combinations of products.
Cisco NX-OS Software
for Nexus 4000 Series Base, 4.1(2)E1(1), 4.1(2)E1(1b), 4.1(2)E1(1d), 4.1(2)E1(1e), 4.1(2)E1(1f), 4.1(2)E1(1g), 4.1(2)E1(1h), 4.1(2)E1(1i), 4.1(2)E1(1j)
The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.