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HDX - Disable TLS 1.0

Vulnerability Summary

TLS 1.0 is no longer considered a secure protocol and there are a number of vulnerabilities associated with it.  Guidance from many software and browser vendors is to disable TLS 1.0.  The Polycom HDX, now end of sale and support, offers TLS 1.0 on SIP and the web interface connections but it can be disabled for SIP communications by running telnet commands.

Please note that this change only changes the TLS settings for SIP communications.  We have mitigated port 443 using the empty fragment mitigation in the TLSv1.0 + CBC cipher case where HDX prepends a record with an empty plaintext fragment before sending the actual payload. 


Last Update: 3/8/2022
Initial Public Release: 3/9/2020
Advisory ID:  PLYTV20-03


Product Affected
HDX 4000

Prior to 3.1.11

3.1.11 and above
HDX 6000

Prior to 3.1.11

3.1.11 and above
HDX 7000

Prior to 3.1.11

3.1.11 and above
HDX 8000

Prior to 3.1.11

3.1.11 and above
HDX 9000

Prior to 3.1.11

3.1.11 and above

HDX software 3.1.11 or higher will need to be installed for this command to work and it is strongly recommended that customers update to the latest release which can be found on Poly Support.

Telnet to the HDX endpoint and log into it with the admin login and password. Then, enter this command: systemsetting enabletlsv1 0 <enter> This disables TLS 1.0 on SIP communications

The HDX will reboot after you hit the enter key.  Once it has rebooted, TLS 1.0 will be disabled for SIP communications.  If you need to enable TLS 1.0 on SIP again, follow the same process but use this command: systemsetting enabletlsv1 1 <enter>  This enables TLS 1.0 on SIP communications.


Note Regarding TLS 1.1

TLS 1.1 cannot be disabled on the HDX.  Both it and TLS 1.2 will be offered on connections.  The HDX family is end of life and no further development will be done on it.


Any customer using an affected system who is concerned about this vulnerability within their deployment should contact Poly Technical Support(888) 248-4143, (916) 928-7561, or visit the Poly Support Site.


Revision History
1.0 9/7/2021 Initial Release
2.0 3/9/2022 Format changes and Detail clarifications