593282 - https://webmail.kabelbw.de uses a very weak (256-bit) Diffie-Hellman key for DHE_RSA SSL cipher suites.

Status: RESOLVED WORKSFORME

(Tech Evangelism Graveyard :: German, defect)

Description

[Bernd Kuebler]

User-Agent:       Mozilla/5.0 (Windows NT 5.1; rv:2.0b4) Gecko/20100818 Firefox/4.0b4
Build Identifier: Mozilla/5.0 (Windows NT 5.1; rv:2.0b4) Gecko/20100818 Firefox/4.0b4

The site http://www.kabelbw.de/webmail can't be open with Firefox 4b4. No problem before with Firefox and with Internet Explorer.

Error Code: ssl_error_rx_malformed_server_key_exch

Reproducible: Always

Steps to Reproduce:
1. got to url http://www.kabelbw.de/webmail
2.
3.

Comment 1

[Matthias Versen [:Matti]]

confirming with Seamonkey trunk but this could be a server issue

Comment 2

[Kaspar]

Another server which proposes an extremely small DHE key (256 bits) in the SSL handshake. It identifies itself in the "Server" header as "Resin/3.0.12".

(In reply to comment #0)
> The site http://www.kabelbw.de/webmail can't be open with Firefox 4b4. No
> problem before with Firefox and with Internet Explorer.

Note that this http URL actually redirects to https://webmail.kabelbw.de/?l=de-DE&v=kabelbw.

Comment 3

[Nelson Bolyard (seldom reads bugmail)]

Server was behaving insecurely before FF 4b4, but FF wasn't detecting it until
4b4.  Mozilla's solution for the next beta is to abandon forward secrecy. :(

Comment 4

[Wan-Teh Chang]

Bernd:

Thank you for the bug report.  I'm going to use this bug
report as a Technical Evangelism bug.

Since you have a @kabelbw.de email address, are you an
employee of Kabel BW?  Or are you a customer of their
Internet service?  Can you help me forward the following
message to the administrator of https://webmail.kabelbw.de?

The server uses a very weak (256-bit) Diffie-Hellman key for
DHE_RSA SSL cipher suites.

To fix this server configuration problem, either
- use a 1024-bit Diffie-Hellman key for the DHE_RSA SSL cipher
  suites, or
- disable all DHE SSL cipher suites.

The latter may be easier to do.

Comment 5

[Wan-Teh Chang]

https://webmail.kabelbw.de/ has disabled all DHE SSL cipher suites.
Marked the bug fixed.

Comment 6

[Wan-Teh Chang]

Reopened the bug.  The error is intermittent.  Perhaps the website
consists of multiple servers, and only some of them disabled DHE
SSL cipher suites.

Comment 7

[Wan-Teh Chang]

This is the cipher suite list of a bad server of https://webmail.kabelbw.de/ captured by Qualys SSL Labs:

SSL Report: webmail.kabelbw.de (213.46.255.23)

Cipher Suites (sorted; server has no preference)
TLS_RC4_128_EXPORT40_WITH_MD5 (0x20080)   WEAK	40
TLS_RC2_128_CBC_EXPORT40_WITH_MD5 (0x40080)   WEAK	40
TLS_RSA_EXPORT_WITH_RC4_40_MD5 (0x3)   WEAK	40
TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5 (0x6)   WEAK	40
TLS_RSA_EXPORT_WITH_DES40_CBC_SHA (0x8)   WEAK	40
TLS_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA (0x14)   WEAK	40
TLS_DES_64_CBC_WITH_MD5 (0x60040)   WEAK	56
TLS_RSA_WITH_DES_CBC_SHA (0x9)   WEAK	56
TLS_DHE_RSA_WITH_DES_CBC_SHA (0x15)   WEAK	56
TLS_RSA_EXPORT1024_WITH_DES_CBC_SHA (0x62)   WEAK	56
TLS_RSA_EXPORT1024_WITH_RC4_56_SHA (0x64)   WEAK	56
TLS_RC4_128_WITH_MD5 (0x10080)	128
TLS_RC2_128_CBC_WITH_MD5 (0x30080)	128
TLS_RSA_WITH_RC4_128_MD5 (0x4)	128
TLS_RSA_WITH_RC4_128_SHA (0x5)	128
TLS_RSA_WITH_AES_128_CBC_SHA (0x2f)	128
TLS_DHE_RSA_WITH_AES_128_CBC_SHA (0x33)	128
TLS_DES_192_EDE3_CBC_WITH_MD5 (0x700c0)	168
TLS_RSA_WITH_3DES_EDE_CBC_SHA (0xa)	168
TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA (0x16)	168
TLS_RSA_WITH_AES_256_CBC_SHA (0x35)	256
TLS_DHE_RSA_WITH_AES_256_CBC_SHA (0x39)	256

This is the cipher suite list of a good server of https://webmail.kabelbw.de/ captured by Qualys SSL Labs:

SSL Report: webmail.kabelbw.de (213.46.255.23)

Cipher Suites (sorted; server has no preference)
TLS_RSA_WITH_NULL_MD5 (0x1)   INSECURE	0
TLS_RSA_WITH_NULL_SHA (0x2)   INSECURE	0
TLS_RC4_128_EXPORT40_WITH_MD5 (0x20080)   WEAK	40
TLS_RC2_128_CBC_EXPORT40_WITH_MD5 (0x40080)   WEAK	40
TLS_RSA_EXPORT_WITH_RC4_40_MD5 (0x3)   WEAK	40
TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5 (0x6)   WEAK	40
TLS_RSA_EXPORT_WITH_DES40_CBC_SHA (0x8)   WEAK	40
TLS_DES_64_CBC_WITH_MD5 (0x60040)   WEAK	56
TLS_RSA_WITH_DES_CBC_SHA (0x9)   WEAK	56
TLS_RSA_EXPORT1024_WITH_DES_CBC_SHA (0x62)   WEAK	56
TLS_RSA_EXPORT1024_WITH_RC4_56_SHA (0x64)   WEAK	56
TLS_RC4_128_WITH_MD5 (0x10080)	128
TLS_RC2_128_CBC_WITH_MD5 (0x30080)	128
TLS_RSA_WITH_RC4_128_MD5 (0x4)	128
TLS_RSA_WITH_RC4_128_SHA (0x5)	128
TLS_RSA_WITH_AES_128_CBC_SHA (0x2f)	128
TLS_DES_192_EDE3_CBC_WITH_MD5 (0x700c0)	168
TLS_RSA_WITH_3DES_EDE_CBC_SHA (0xa)	168
TLS_RSA_WITH_AES_256_CBC_SHA (0x35)	256

Comment 8

[Matthias Versen [:Matti]]

I've contacted them via email form

Comment 9

[Virtual_ManPL [:Virtual] 🇵🇱 - (please needinfo? me - so I will see your comment/reply/question/etc.)]

I can't reproduce it with latest Nightly, so I'm marking this bug as WORKSFORME.
If you still can reproduce it, please reopen this bug.

Comment 10

[Rez]

I've been using this version of SeaMonkey since it came out and today is the first time I've seen this error:

An error occurred during a connection to pop.1and1.com:995.
SSL received a malformed Server Key Exchange handshake message.
(Error code: ssl_error_rx_malformed_server_key_exch)

This mailbox worked fine half an hour ago, but just now I got this error multiple times when trying to check mail. 

My other mailbox on the same domain is working fine.

Build identifier: Mozilla/5.0 (Windows NT 5.1; rv:8.0.1) Gecko/20111121 Firefox/8.0.1 SeaMonkey/2.5

Comment 11

[Virtual_ManPL [:Virtual] 🇵🇱 - (please needinfo? me - so I will see your comment/reply/question/etc.)]

(In reply to Rez from comment #10)
> I've been using this version of SeaMonkey since it came out and today is the
> first time I've seen this error:
> 
> An error occurred during a connection to pop.1and1.com:995.
> SSL received a malformed Server Key Exchange handshake message.
> (Error code: ssl_error_rx_malformed_server_key_exch)
> 
> This mailbox worked fine half an hour ago, but just now I got this error
> multiple times when trying to check mail. 
> 
> My other mailbox on the same domain is working fine.
> 
> Build identifier: Mozilla/5.0 (Windows NT 5.1; rv:8.0.1) Gecko/20111121
> Firefox/8.0.1 SeaMonkey/2.5

Can you still reproduce it with latest version of SeaMonkey with a clean fresh new profile without any addons and plugins?

Comment 12

[Rez]

It reproduced every time I tried to access that mailbox until I restarted SM, then it went away and I haven't seen it again. I think it goes to show the bug is still here, but what triggers it? I'd never seen it before and I've been using SM since it was new, and I've had that mailbox since 2003. Might it only happen in response to a particular server glitch, or to an unstable connection? (My DSL likes to cut out regularly cuz the phone line is ****, but that's not new.)

I don't have a lot of add-ons, and have not added or updated any in a long time.

Well, if I see it again, I'll know where to report it. Will be installing a fresh version pretty soon, and I can break anything. :)