A vulnerability in the implementation of the inter-VM channel of Cisco IOS Software for Cisco 809 and 829 Industrial Integrated Services Routers (Industrial ISRs) and Cisco 1000 Series Connected Grid Routers (CGR1000) could allow an unauthenticated, adjacent attacker to execute arbitrary shell commands on the Virtual Device Server (VDS) of an affected device.
The vulnerability is due to insufficient validation of signaling packets that are destined to VDS. An attacker could exploit this vulnerability by sending malicious packets to an affected device. A successful exploit could allow the attacker to execute arbitrary commands in the context of the Linux shell of VDS with the privileges of the root user. Because the device is designed on a hypervisor architecture, exploitation of a vulnerability that affects the inter-VM channel may lead to a complete system compromise.
For more information about this vulnerability, see the Details section of this advisory.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link:
This advisory is part of the June 3, 2020, release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication, which includes 23 Cisco Security Advisories that describe 25 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: June 2020 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.
This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco IOS Software:
- Cisco 809 and 829 Industrial ISRs
For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect the following Cisco products:
- 800 Series ISRs
- 807 Industrial ISRs
- IOS XE Software
- IOS XR Software
- NX-OS Software
Cisco 800 Series Industrial ISRs and Cisco CGR1000 devices are designed on a hypervisor architecture, where Cisco IOS Software, a Guest Operating System (Guest OS), and VDS run as separate virtual machines (VMs). Cisco IOS Software and Guest OS need to access some shared devices. Examples are embedded multimedia card (eMMC) flash memory, USB ports, and the console. VDS coordinates access to the shared devices and provides communication channels between VMs over emulated Ethernet interfaces.
Cisco IOS Software and VDS perform inter-VM signaling and control operations over a UDP channel on UDP port 9700. The attacker could gain full control of the VDS and compromise the system completely because signaling packets are not restricted—they are not processed only when they are sent to internal, local communications between VMs. Instead, an affected system will accept and process signaling packets from any interface of an affected device. Successful exploitation could allow the attacker to gain full control of VDS, which could lead to a complete system compromise, including compromise of the Cisco IOS Software VM and the Guest OS VM.
There are no workarounds that address this vulnerability.
Customers can reduce the attack surface by restricting inbound traffic destined for UDP port 9700 of an affected device by implementing an access control list (ACL) or infrastructure access control list (iACL). This may be a suitable mitigation until affected devices can be upgraded. Information about access lists is in Cisco Guide to Harden Cisco IOS Devices. Information about iACLs is in Protecting Your Core: Infrastructure Protection Access Control Lists.
Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC:
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Cisco IOS Software
To help customers determine their exposure to vulnerabilities in Cisco IOS Software, Cisco provides the Cisco Software Checker to identify any Cisco Security Advisories that impact a specific Cisco IOS Software release and the earliest release that fixes the vulnerabilities described in each advisory (“First Fixed”). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities described in all the advisories identified (“Combined First Fixed”).
Customers can use the Cisco Software Checker to search advisories in the following ways:
- Choose the software and one or more releases
- Upload a .txt file that includes a list of specific releases
- Enter the output of the show version command
After initiating a search, customers can customize the search to include all Cisco Security Advisories, a specific advisory, or all advisories in the most recent bundled publication.
Customers can use the following form to determine whether a release is affected by any Cisco Security Advisory by entering a Cisco IOS Software release—for example, 15.1(4)M2:
By default, the Cisco Software Checker includes results only for vulnerabilities that have a Critical or High Security Impact Rating (SIR). To include results for Medium SIR vulnerabilities, customers can use the Cisco Software Checker on Cisco.com and check the Medium check box in the drop-down list under Impact Rating when customizing a search.
Fixed Releases for All VDS-Related Vulnerabilities in This Bundle of Advisories
This release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication contains multiple advisories for vulnerabilities that affect VDS. To help ensure a complete upgrade solution for these vulnerabilities, administrators are advised to upgrade affected devices to a fixed software release that addresses all VDS-related advisories in this bundled publication:
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.
This vulnerability was found during internal security testing by X.B. of the Cisco Advanced Security Initiatives Group (ASIG) and E.I. of Cisco PSIRT.
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.
Version Description Section Status Date 1.0 Initial public release. — Final 2020-JUN-03
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