Introduction
This document describes the solution for Cisco IP Phones 7800/8800 Series registration failure over MRA (Mobile Remote Access) if phone has expired Sectigo/Addtrust root certificate which expried on 30th May 2020.
Prerequisites
Requirements
There are no specific requirements for this document.
Components Used
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Problem
Cisco IP Phones 7800/8800 Series fails to register over MRA if phone has expired Sectigo/Addtrust root certificate which expried on 30th May 2020 and Expressway has signed it certfictate from Sectigo/Addtrust CA.
Per 12.7 firmware Certificate Authority Trust List, Trust list has expired Sectigo/Addtrust certificate on IP phone trust store.
https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/cuipph/all_models/ca-list/CA-Trust-List.pdf
To verify the certificate validity copy the fingerprint mentioned in document for certificate trust store and browse to https://crt.sh/ paste the fingerprint in the white box and click search
Once search is completed you can verify the validity of the certificate
Solution
Firmware to 12.8 has a fix wherein expired certificates have been cleaned,This issue is documented by Cisco bug ID CSCvt26128.
You can download the latest firmware thru links documented below for 7800 and 8800 Series Phones
https://www.cisco.com/web/software/282074288/151637/cmterm-78xx.12-8-1-0001-455-readme.html
cmterm-78xx.12-8-1-0001-455.k3.cop.sgn
https://www.cisco.com/web/software/282074288/151637/cmterm-8845_8865.12-8-1-0001-455-readme.html
cmterm-8845_65-sip.12-8-1-0001-455.k3.cop.sgn
https://www.cisco.com/web/software/282074288/151637/cmterm-88xx.12-8-1-0001-455-readme.html
cmterm-88xx-sip.12-8-1-0001-455.k3.cop.sgn
Limitation
Note : Phone firmwares upgrade over MRA isn't supported. This issue is documented by Cisco bug ID CSCvb29314.