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Systems Affected
All the systems affected are mentioned here: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170317-cmp
Threat Level
Overview
Vulnerability in the Cisco Cluster Management Protocol (CMP) processing code in Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a reload of an affected device or remotely execute code with elevated privileges.
Description
The Cluster Management Protocol utilizes Telnet internally as a signaling and command protocol between cluster members. The vulnerability is due to the combination of two factors:
The failure to restrict the use of CMP-specific Telnet options only to internal, local communications between cluster members and instead accept and process such options over any Telnet connection to an affected device, and
The incorrect processing of malformed CMP-specific Telnet options.
An attacker could exploit this vulnerability by sending malformed CMP-specific Telnet options while establishing a Telnet session with an affected Cisco device configured to accept Telnet connections. An exploit could allow an attacker to execute arbitrary code and obtain full control of the device or cause a reload of the affected device.
Cisco will release software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Impact
Indicators of Compromise
Cisco IPS Signature 7880-0 and Snort SIDs 41909 and 41910 can detect attempts to exploit this vulnerability..
Solution/ Workarounds
There are no workarounds that address this vulnerability.
Disabling the Telnet protocol as an allowed protocol for incoming connections would eliminate the exploit vector. Disabling Telnet and using SSH is recommended by Cisco. Information on how to do both can be found on the Cisco Guide to Harden Cisco IOS Devices.
Customers unable or unwilling to disable the Telnet protocol can reduce the attack surface by implementing infrastructure access control lists (iACLs). Information on iACLs can be found on the following document: Protecting Your Core: Infrastructure Protection Access Control Lists
References
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170317-cmp
Disclaimer
The information provided herein is on "as is" basis, without warranty of any kind.
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