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POLY SYSTEMS - H323 AND SIP AES ENCRYPTION IMPACT

As more video conference calls are conducted over public networks and public environments, the need to deploy security measures to protect the information discussed in the call rises. Conducting video conferences behind firewalls or over ISDN based networks reduce the potential for call tapping, although there is still residual risk. Encryption solutions can assist with call privacy, even when calls are made over the public internet. This document explains the details of Poly's implementation of H.323 and SIP Media Encryption using the Advanced Encryption Standard (“AES”), which provides privacy during a video conference call. Specific details are then also provided for all Poly® Video endpoint and MCU products.

Severity

Medium

Advisory ID

PLYGN16-01

Initial public release

02/3/2016

Last update

03/11/2022

Category

Poly

Summary

Standard Encryption

Poly® products use the Advanced Encryption Standard (“AES”) as approved by the National Institute of Standards and Technology (“NIST”) for encryption of digital information. When deployed within communication systems, AES ensures that the information discussed within a call is unintelligible to unauthorized parties that may have tapped into the communication system.

AES Media Encryption Technical Notes

  • AES media encryption does not change the MTU (Maximum Transmission Unit) size. The endpoint reduces the payload as needed to comply with the configured MTU. Thus, the media payload within packets in an encrypted call will be smaller than those in an unencrypted call.
  • AES media encryption does not introduce any extra latency.
  • AES media encryption adds between 0-15 bytes of overhead per media packet.

Poly® H.323 Media Encryption Implementation

All currently shipping Poly® H.323 products support media encryption in H.323 calls using the mechanisms defined in H.235v3 (equivalently, per H.235.6), using encrypted RTP with native H.235/H.245 Diffie-Hellman key exchange).

Table 1 shows the specific details of the support by product. All products have “baseline” support; some products have additional support as listed.

Product

AES-128 Support

AES-256 Support

Baseline Support (All Products)

Supported (AES-CBC-128) (DH 1024)

Not Supported

Poly® HDX® (Version 3.1.x or later)

Supported (AES-CBC-128) (DH 1024)

Supported (AES-CBC-256) (DH 2048)

Poly® RealPresence® Group Series

Supported (AES-CBC-128) (DH 1024)

Supported (AES-CBC-256) (DH 2048)

See the individual product administrative and user guides for details on how to configure and use H.323 media encryption (administrative and user guides are available at https://www.poly.com/us/en/support in the “DOCUMENTS & DOWNLOADS” area).

Verifying secured connections

Poly® HDX® and Poly® RealPresence® Group Series endpoints support the display of an “encryption check code”, which can be used to detect whether a Man-In-The-Middle (MITM) attack is underway in an H.323 call. The check code is displayed in the endpoint call statistics in the form of a long hexadecimal number. After an encrypted H.323 call has been established, the user at one end reads the check code out loud while a user on the other end verifies it. If the codes match, the call is secure; if they do not match, the Diffie-Hellman key exchange has been compromised and the call should be considered insecure. See the product user guides for additional details on this mechanism.

Poly® SIP Media Encryption Implementation

All currently shipping Poly® SIP products support media encryption in SIP calls per RFCs 3711 (SRTP), 4568 (SDP Security Descriptions for Media Streams) and 6188 (AES-192 and AES-256 usage in SRTP). RFC 4568 key exchange requires the use of TLS as the SIP transport protocol; media encryption is not available when using SIP/UDP or SIP/TCP. Refer to the product administration guides for details on how to ensure that TLS is configured as the SIP transport protocol (configured as part of “Secure Communication Mode” on the RMX; part of the “Local Cluster > Signaling Settings” on DMA; configured as the SIP “Transport Protocol” on Poly endpoints).

Table 2 shows the specific details of the support by product. All products have “baseline” support; some products have additional support as listed.

Product

AES-128 Support

AES-256 Support

Baseline Support (All Products)

Supported (AES_CM_128_HMAC_SHA1_80)

Not Supported

Poly® RealPresence® Collaboration Server (RMX®) (Version 8.1.4 or later)

Supported (AES_CM_128_HMAC_SHA1_80) (AES_CM_128_HMAC_SHA1_32)

Not Supported

Poly® HDX® (Version 3.1.x or later)

Supported (AES_CM_128_HMAC_SHA1_80)

Supported (AES_CM_256_HMAC_SHA1_80)

Poly® RealPresence® Group Series (Version 4.1 or later)

Supported (AES_CM_128_HMAC_SHA1_80) (AES_CM_128_HMAC_SHA1_32)

Supported (AES_CM_256_HMAC_SHA1_80) (AES_CM_256_HMAC_SHA1_32)

Table 1 - H.323 Media Encryption Support

Key exchange is performed in-band over the TLS-secured SIP signaling channel according to RFC 4568.

Media Encryption in SIP calls using TIP

Poly® HDX® endpoints (version 3.0.2 and later) and Poly® RealPresence® Collaboration Server (RMX®) (version 7.6 and later) also support SIP media encryption in calls using Telepresence Interoperability Protocol (TIP). In addition to the same baseline SRTP media encryption support as documented above, these products include support for the following:

Resolution

There is no workaround.

Revision history

This document has been revised according to the following information.

List of versions

Version

Description

Date

2.0

Format Changes

03/11/2022

1.1

Updated Content and Formatting

02/09/2016

1.0

Original Publication

2/3/2016

Additional information

Follow these links for additional information.

Third-party security patches

Third-party security patches that are to be installed on systems running Poly software products should be applied in accordance with the customer's patch management policy.

Contact

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.

Security bulletin archive

To view released Security Bulletins, visit https://support.hp.com/security-bulletins.

It is strongly recommended that security related information being communicated to HP be encrypted using PGP, especially exploit information.

Download HP’s security-alert PGP key

Legal information

©2022 Plantronics, Inc. All rights reserved.

TrademarksPoly, the propeller design, and the Poly logo are trademarks of Plantronics, Inc. All other trademarks are property of their respective owners. No portion hereof may be reproduced or transmitted in any form or by any means, for any purpose other than the recipient's personal use, without the express written permission of Poly.

DisclaimerWhile Poly uses reasonable efforts to include accurate and up-to-date information in this document, Poly makes no warranties or representations as to its accuracy. Poly assumes no liability or responsibility for any typographical errors, out of date information, or any errors or omissions in the content of this document. Poly reserves the right to change or update this document at any time. Individuals are solely responsible for verifying that they have and are using the most recent Technical Bulletin.

Limitation of LiabilityPoly and/or its respective suppliers make no representations about the suitability of the information contained in this document for any purpose. Information is provided "as is" without warranty of any kind and is subject to change without notice. The entire risk arising out of its use remains with the recipient. In no event shall Poly and/or its respective suppliers be liable for any direct, consequential, incidental, special, punitive, or other damages whatsoever (including without limitation, damages for loss of business profits, business interruption, or loss of business information), even if Poly has been advised of the possibility of such damages.



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