Cisco Nexus 1000V contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are not available.
A vulnerability in the Cisco Nexus 1000V could allow an unauthenticated, remote attacker to cause a Virtual Supervisor Module (VSM) to report a Virtual Ethernet Module (VEM) as unavailable.
The vulnerability is due to insufficient prioritization for VSM/VEM heartbeat messages. An attacker could exploit this vulnerability by preventing the successful delivery of heartbeat messages between a VSM and a VEM with a UDP flood, causing the VSM to report the affected VEMs as unavailable.
Cisco would like to thank Felix 'FX' Lindner, Recurity Labs GmbH, for reporting this issue to us.
Cisco has confirmed the vulnerability in a security notice; however, software updates are not available.
At the time this alert was first published, Cisco NX-OS Software for Nexus 1000 Series 4.2(1)SV1(5.1) and prior are vulnerable. Later releases of Cisco NX-OS Software for Nexus 1000 Series may also be affected.
To exploit this vulnerability, the attacker would likely need access to a trusted, internal network in which the targeted device may reside. This access restriction limits the possibility of a successful exploit.
Customers are advised to review the bug reports in the "Vendor Announcements" section for a current list of affected versions.
An unauthenticated, remote attacker could exploit this vulnerability to cause the VSM to report VEMs on an affected device as unavailable, resulting in a denial of service (DoS) condition.
The vulnerability is due to insufficient prioritization for VSM/VEM heartbeat messages.
An unauthenticated, remote attacker could exploit this vulnerability by conducting a UDP flood attack, which could cause an unsuccessful delivery of heartbeat messages between a VSM and a VEM. As a result, the VSM would report the VEM as unavailable, resulting in a DoS condition.
Administrators are advised to contact the vendor regarding future updates and releases.
Administrators are advised to allow only trusted users to have network access.
The security vulnerability applies to the following combinations of products.
Cisco NX-OS Software
for Nexus 1000 Series 4.2(1)SV1(5.1)
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.