Connectrix B-Series: The Web Browsers Report "Cipher Mismatch, No Matching Ciphers" When Accessing WebTools UI Using HTTPS

Summary: AES256-SHA256 (0x3d) and AES128-SHA256 (0x3c) is blocked for TLS.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.

Symptoms

The web browsers (Chrome, New Edge, or Firefox) refused to open the WebTools using HTTPS.

The error message contains "Cipher Mismatch" or "No Matching Ciphers."
 
Screenshot of Error Message Showing Connection Not Secure, Unsupported Protocol
Figure 1: Screenshot of Error Message Showing Connection Not Secure, Unsupported Protocol

The switch is running in FOS 8.1 or 8.2 firmware.
 

Cause

The switch HTTPS cipher setting only allows AES256-SHA256 and AES128-SHA256 for TLS 1.2 (the "default_generic" or "default_strong templates" of FOS 8.1 or 8.2).
<switchname>:root> seccryptocfg --show | grep HTTPS
HTTPS                    : !ECDH:!DH:HIGH:-MD5:!CAMELLIA:!SRP:!PSK:!AESGCM:!SSLv3
HTTPS                    : TLSv1.2

<switchname:root> openssl ciphers -v '!ECDH:!DH:HIGH:-MD5:!CAMELLIA:!SRP:!PSK:!AESGCM:!SSLv3'
AES256-SHA256           TLSv1.2 Kx=RSA      Au=RSA  Enc=AES(256)  Mac=SHA256
AES128-SHA256           TLSv1.2 Kx=RSA      Au=RSA  Enc=AES(128)  Mac=SHA256

The Wireshark dump shows that the client does not accept AES256-SHA256 (0x3d) or AES128-SHA256 (0x3c), hence the TLS handshake fails.
 
Screenshot of Wireshark Dump Showing Handshake Failure
Figure 2: Screenshot of Wireshark Dump Showing Handshake Failure

Resolution

Modify the switch HTTPS cipher setting to cover the client. 

Example:
In this example, the current HTTPS cipher setting is "!ECDH:!DH:HIGH:-MD5:!CAMELLIA:!SRP:!PSK:!AESGCM:!SSLv3"

To enable AES256-GCM-SHA384 (0x9d) and AES128-GCM-SHA256 (0x9c), remove "!AESGCM" from the setting with the command:
seccryptocfg --replace -type https -cipher '!ECDH:!DH:HIGH:-MD5:!CAMELLIA:!SRP:!PSK:!SSLv3'

Additional Information

Map OpenSSL cipher names (displayed in the OpenSSL command) with IANA cipher names (displayed in Wireshark dump) using the Mozilla document, Security/Cipher Suites - MozillaWiki This hyperlink is taking you to a website outside of Dell Technologies.

Affected Products

Connectrix B-Series
Article Properties
Article Number: 000213633
Article Type: Solution
Last Modified: 25 Aug 2023
Version:  5
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