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TLS Cipher Error

I was wondering if anyone else has been seeing TLS errors on incoming email to an ESA on 8.0.0-617? The senders report this error "(Certificate rejected over TLS. (wrong cipher returned))" and in my logs I see this:

(ICID xxx) TLS failed. Reason: (336151575, 'error:14094417:SSL routines:SSL3_READ_BYTES:sslv3 alert illegal parameter').

This has caused email from critical partners to fail since it is a perm failure.

I tracked the issue down to a cipher mismatch in the TLS implementation. When you view the full list of ciphers that the ESA supports, the first two in the list are only definied in TLS v1.2 (2008). The problem is that the ESA's TLS implementation doesn't include any TLS extensions past v1.0 (2005). In fact, the "Cisco" OpenSSL version is based on 0.9.8. (sigh)

What happens is the ESA advertises TLS v1.0 and then wants to use a cipher from v1.2 so some clients are freaking out because if you take the RFCs literally, this is a mismatch. I have verified that McAfee MTAs are exhibiting this behavior. I did contact TAC but they say no one has raised this issue before and it is not an RFC implementation error because "it doesn't matter what ciphers are used".

Has anyone else seen this error? As far as I can see if there is a mismatch the client will never successfully connect.

(ICID xxx) TLS failed. Reason: (336151575, 'error:14094417:SSL routines:SSL3_READ_BYTES:sslv3 alert illegal parameter').

I did see this thread from a few months ago about this but nothing else.

https://supportforums.cisco.com/thread/2230409

These are the two ciphers in question.

DHE-RSA-AES256-SHA256

DHE-DSS-AES256-SHA256

https://www.openssl.org/docs/apps/ciphers.html

TLS 1.0: RFC2246 – January, 1999

                OpenSSL 0.9.2.b – March, 1999

                OpenSSL 0.9.3 – May, 1999

                OpenSSL 0.9.4 – August, 1999

                OpenSSL 0.9.5 – February, 2000

                OpenSSL 0.9.6 – September, 2000

TLS 1.0: AES cipher enhancements – June, 2002

                OpenSSL 0.9.7 – December, 2002

TLS 1.0: Camellia cipher enhancements – July, 2005

                OpenSSL 0.9.8 – July, 2005

TLS 1.0: SEED cipher enhancements – August, 2005 (NOT IMPLEMENTED)

TLS 1.1: RFC4346 – April, 2006 (NOT IMPLEMENTED)

TLS 1.2: RFC5246 – August, 2008 (NOT IMPLEMENTED)

To view the complete list of ciphers, use sslconfig, verify, <ENTER>

Everyone's tags (2)
7 REPLIES
New Member

TLS Cipher Error

I have this issue as well and was told that this is an open defect within 8.0.1-023.  Should be fixed in 8.0.2, but no ETA.

Cisco Employee

TLS Cipher Error

Hi Bob,

The change below has fixed the issue for 8.0.1 customers, please let us know if we can help with anything else.

1.  Log into the CLI of the ESA and issue the 'sslconfig' command:
ironport> sslconfig

sslconfig settings:
  GUI HTTPS method:  sslv3tlsv1
  GUI HTTPS ciphers: RC4-SHA:RC4-MD5:ALL
  Inbound SMTP method:  sslv3tlsv1
  Inbound SMTP ciphers:
  Outbound SMTP method:  sslv3tlsv1
  Outbound SMTP ciphers: RC4-SHA:RC4-MD5:ALL

2.  When prompted for the operation to perform enter 'INBOUND'

Choose the operation you want to perform:
- GUI - Edit GUI HTTPS ssl settings.
- INBOUND - Edit Inbound SMTP ssl settings.
- OUTBOUND - Edit Outbound SMTP ssl settings.
- VERIFY - Verify and show ssl cipher list.
[]>INBOUND

3.  When prompted for inbound SMTP ssl method to use enter '5'

Enter the inbound SMTP ssl method you want to use.
1. SSL v2.
2. SSL v3
3. TLS v1
4. SSL v2 and v3
5. SSL v3 and TLS v1
6. SSL v2, v3 and TLS v1
[5]> 5

4.  When prompted for the ssl cipher you want to use paste in the following
'MEDIUM:HIGH:-SSLv2:-aNULL:@STRENGTH:!DHE-RSA-AES256-SHA256:!DHE-RSA-AES128-SHA256'

Enter the inbound SMTP ssl cipher you want to use.
[]>MEDIUM:HIGH:-SSLv2:-aNULL:@STRENGTH:!DHE-RSA-AES256-SHA256:!DHE-RSA-AES128-SHA256

5.  Press Enter to return to main menu
6. Repeat steps 1-5 and at step 2 specify OUTBOUND to apply the same settings to your outbound ciphers

7.  Type commit to commit changes
New Member

TLS Cipher Error

I also see this error in TLS negotiations.  My C670s are currenting running in FIPS mode and I offer STARTTLS to most external SMTP servers.  In a small percentage of connections the external SMTP server is able to do TLS but not any that are FIPS approved, most of the connections can then negotiate a plain text connection but some cannot and give errors very similar to the ones you listed.  My only course of action is to get the external SMTP server admins to add a TLS cipher that the C670s will allow in FIPS mode:

DHE-RSA-AES256-SHA                    SSLv3 Kx=DH       Au=RSA  Enc=AES(256)  Mac=SHA1

DHE-DSS-AES256-SHA                    SSLv3 Kx=DH       Au=DSS  Enc=AES(256)  Mac=SHA1

AES256-SHA                                       SSLv3 Kx=RSA      Au=RSA  Enc=AES(256)  Mac=SHA1

DHE-RSA-AES128-SHA                    SSLv3 Kx=DH       Au=RSA  Enc=AES(128)  Mac=SHA1

DHE-DSS-AES128-SHA                    SSLv3 Kx=DH       Au=DSS  Enc=AES(128)  Mac=SHA1

AES128-SHA                                       SSLv3 Kx=RSA      Au=RSA  Enc=AES(128)  Mac=SHA1

EDH-RSA-DES-CBC3-SHA               SSLv3 Kx=DH       Au=RSA  Enc=3DES(168) Mac=SHA1

EDH-DSS-DES-CBC3-SHA               SSLv3 Kx=DH       Au=DSS  Enc=3DES(168) Mac=SHA1

DES-CBC3-SHA                                  SSLv3 Kx=RSA      Au=RSA  Enc=3DES(168) Mac=SHA1

Or modify my HAT to set them to a no TLS sender group, painful either way.

Cisco Employee

TLS Cipher Error

Jason,

Thanks for sharing, care to send me an email directly and we can take a look ?

sbayer at cisco dot com

Regards,

Stephan

New Member

Re: TLS Cipher Error

The next time it occurrs I'll ping you with more of the details. 

Here's what I can share with you on the last occurrence:

The e-mail is never successfully sent to our applince. 

The sending side receives the following error:

Subject: Warning: could not send message for past 4 hours

    **********************************************

    **      THIS IS A WARNING MESSAGE ONLY      **

    **  YOU DO NOT NEED TO RESEND YOUR MESSAGE  **

   **********************************************

The original message was received at Fri, 7 Feb 2014 16:09:03 -0600

from (hostname/IP addrress removed)

   ----- Transcript of session follows -----

<(removed)@nebraska.gov>... Deferred: 403 4.7.0 TLS handshake failed.

Warning: message still undelivered after 4 hours

Will keep trying until message is 5 days old

In my mail_logs I have:

Tue Feb 11 08:26:49 2014 Info: ICID 39917017 TLS failed: (336151575, 'error:14094417:SSL routines:SSL3_READ_BYTES:sslv3 alert illegal parameter')

Tue Feb 11 08:26:49 2014 Info: ICID 39917017 lost

Tue Feb 11 08:26:49 2014 Info: ICID 39917017 close

Here's a Injection Debug Log from that same IP a little later:

Wed Feb 12 12:34:18 2014 Info: Begin Logfile

Wed Feb 12 12:34:18 2014 Info: Version: 8.0.0-671 SN: Removed

Wed Feb 12 12:34:18 2014 Info: Time offset from UTC: -21600 seconds

Wed Feb 12 13:26:52 2014 Info: 40190812 Sent to IP Address Removed: '220-HostName RemovedESMTP\r\n220 220 MESSAGE REMOVED\r\n'

Wed Feb 12 13:26:52 2014 Info: 40190812 Rcvd from IP Address Removed: 'EHLO Hostname Removed\r\n'

Wed Feb 12 13:26:52 2014 Info: 40190812 Sent to IP Address Removed: '250-Hostname Removed\r\n250-8BITMIME\r\n250-SIZE 104857600\r\n250 STARTTLS\r\n'

Wed Feb 12 13:26:52 2014 Info: 40190812 Rcvd from IP Address Removed: 'STARTTLS\r\n'

Wed Feb 12 13:26:52 2014 Info: 40190812 Sent to IP Address Removed: '220 Go ahead with TLS\r\n'

Wed Feb 12 13:26:52 2014 Info: 40190812 Sent to IP Address Removed: '454 TLS not available due to a temporary reason\r\n'

Wed Feb 12 14:26:51 2014 Info: 40205349 Sent to IP Address Removed: '220-HostName RemovedESMTP\r\n220 220 MESSAGE REMOVED\r\n'

Wed Feb 12 14:26:51 2014 Info: 40205349 Rcvd from IP Address Removed: 'EHLO Hostname Removed\r\n'

Wed Feb 12 14:26:51 2014 Info: 40205349 Sent to IP Address Removed: '250-Hostname Removed\r\n250-8BITMIME\r\n250-SIZE 104857600\r\n250 STARTTLS\r\n'

Wed Feb 12 14:26:51 2014 Info: 40205349 Rcvd from IP Address Removed: 'STARTTLS\r\n'

Wed Feb 12 14:26:51 2014 Info: 40205349 Sent to IP Address Removed: '220 Go ahead with TLS\r\n'

Wed Feb 12 14:26:51 2014 Info: 40205349 Sent to IP Address Removed: '454 TLS not available due to a temporary reason\r\n'

Cisco Employee

Re: TLS Cipher Error

Hi Jason,

Thanks for sharing. The error message looks like there is a cipher mismatch.

What you can do:

1. >sslconfig >verify

paste in the cipher string from inbound and outbound above

MEDIUM:HIGH:-SSLv2:-aNULL:@STRENGTH:!DHE-RSA-AES256-SHA256:!DHE-RSA-AES128-SHA256

this shows the list of ciphers available. Then compare to yours. What's different, what's missing?

If you could open a support case we can also provide a more thorough investigation. Hope that helps.

Stephan

New Member

Re: TLS Cipher Error

Stephan,

Here's the results of my SSLCONFIG command:

sslconfig settings:

  GUI HTTPS method:  tlsv1

  GUI HTTPS ciphers: FIPS

  Inbound SMTP method:  tlsv1

  Inbound SMTP ciphers: FIPS

  Outbound SMTP method:  tlsv1

  Outbound SMTP ciphers: FIPS:-aNULL

If I disable FIPS mode and modify the TLS ciphers, will that stick after I re-enable FIPS mode?

I did start a support ticket on the issue.

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