Cisco MDS 9000 NX-OS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
A vulnerability in the supervisor of the Cisco MDS Family could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
The vulnerability is due to improper handling of Virtual Router Redundancy Protocol (VRRP) frames. An attacker could exploit this vulnerability by sending a VRRP frame with Authentication Header (AH) authentication. An exploit could allow an attacker to drive CPU utilization over 90 percent, causing the supervisor to be slow to respond. The CPU does not recover until the VRRP service is restarted via a system switchover or restart.
Cisco has confirmed the vulnerability in a security notice and released software updates.
At the time this alert was first published, Cisco MDS 9000 NX-OS Software Releases 5.0 and prior were vulnerable. Later releases of Cisco MDS 9000 NX-OS Software may also be vulnerable.
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-2013-5566
Customers are advised to consult Cisco bug ID CSCte27874 for the most complete list of affected product versions.
An unauthenticated, remote attacker could exploit this vulnerability to consume excessive CPU resources on an affected device, resulting in a DoS condition.
The vulnerability is due to improper handling of VRRP frames by the supervisor component of the affected software.
An attacker could exploit this vulnerability by sending a VRRP frame with AH authentication. An exploit could allow an attacker to use a large amount of CPU resources, which could cause the supervisor to be slow to respond, resulting in a 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 firstname.lastname@example.org for assistance.
The security vulnerability applies to the following combinations of products.
Cisco MDS 9000 NX-OS Software
2.1 Base | 3.0 Base | 3.2 Base | 4.1 Base, (1b), (1c), (3a) | 4.2 Base, (1a), (1b), (3) | 5.0 Base
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