Cisco Security Advisory
Cisco Catalyst 6800 Series Switches ROM Monitor Software Secure Boot Bypass Vulnerability
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CVSS:3.0/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
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A vulnerability in Cisco IOS ROM Monitor (ROMMON) Software for Cisco Catalyst 6800 Series Switches could allow an unauthenticated, local attacker to bypass Cisco Secure Boot validation checks and load a compromised software image on an affected device.
The vulnerability is due to the presence of a hidden command in the affected software. An attacker could exploit this vulnerability by connecting to an affected device via the console, forcing the device into ROMMON mode, and writing a malicious pattern to a specific memory address on the device. A successful exploit could allow the attacker to bypass signature validation checks by Cisco Secure Boot technology and load a compromised software image on the affected device. A compromised software image is any software image that has not been digitally signed by Cisco.
There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180926-catalyst6800
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Vulnerable Products
This vulnerability affects the following Cisco devices if they are running a vulnerable release of Cisco IOS ROMMON Software:
- Catalyst 6800 Series Supervisor Engine 6T
- Catalyst 6840-X Series Fixed Backbone Switches
- Catalyst 6880-X Series Extensible Fixed Aggregation Switches
For information about affected software releases, consult the Cisco bug ID(s) at the top of this advisory.
Determining the Cisco IOS ROMMON Software Release
To determine which Cisco IOS ROMMON Software release is running on a device, administrators can log in to the device and use the show version | include ROM: command in the CLI. The following example shows the output of the command for a device that is running Cisco IOS ROMMON Software Release 15.1(02)SY01:
switch# show version | include ROM: ROM: System Bootstrap, Version 15.1(02)SY01 [ Rel 1.1], RELEASE SOFTWARE
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
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For information about fixed software releases, consult the Cisco bug ID(s) at the top of this advisory.
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.
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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.
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This vulnerability was found during internal security testing.
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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.
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Show LessVersion Description Section Status Date 1.0 Initial public release. - Final 2018-September-26
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