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 Virtual Ethernet Module (VEM) kernel driver for VMware ESXi could allow an unauthenticated, remote attacker to cause the ESXi hypervisor to crash, resulting in a purple screen of death (PSOD).
The vulnerability is due to insufficient validation of STUN protocol packets, which results in a crash of the ESXi hypervisor due to an out of bound array index access. An attacker could exploit this vulnerability by sending specially crafted STUN packets to a vulnerable VEM. This vulnerability requires that STUN protocol debugging be enabled on the VEM kernel driver for VMware ESXi.
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 is 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 to send specially crafted STUN packets to a targeted device. 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 VMware ESXi hypervisor to crash, resulting in a denial of service (DoS) condition.
The vulnerability is due to insufficient validation of STUN protocol packets by the Cisco Nexus 1000V VEM kernel driver for the VMware ESXi hypervisor.
An unauthenticated, remote attacker could exploit this vulnerability by sending specially crafted STUN packets to a vulnerable VEM. If successful, the attacker could cause an out of bound array index access, which could cause the ESXi hyperviosr to crash, 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.
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.
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.