SSL Inspection problem

[Jack_T]

Hi all,

I have a Fortigate 90D with Web filter and SSL Inspection enabled.

I can't reach https://www.giustizia.it: with Chrome I receive "ERR_CONNECTION_CLOSED", with Firefox instead "Cannot create secure connection".

If I turn off SSL Inspection I can navigate to the site; I have tried to add an exception in web filter's rules (wildcard, simple, exempt, allow...) but with no luck.

How I can solve this issue?

Thanks in advance

[CÃ_sar_Romero · Accepted solution]

Jack_T wrote:

Hi, I have not exempts under SSL inspections options, maybe I have an old version of fortiOS? Thanks! :)

Exactly, this is available since FortiOS 5.2.

[CÃ_sar_Romero · Accepted solution]

If you don't want problems just follow the Upgrade Path available in the release notes (available at the version folder in support.fortinet.com). In that case you won't lose any configuration.

Regards.

[emnoc · Accepted solution]

I  highly  doubt HSTS is the issue. What you could do is run a non browser http  tool like  curl or ab and see what happens.

As far as  a browser caching a "site" certificate, I never heard of that and that would break every concept of the PKI. Think about it, the  client still sends a hello, the server still send the certificate which has all of the goodies ( serial#, cry details, public-key, issuer,etc....)

Now back to the earlier, what does your  off browser diagnostic shows ( curl, gnutls,openssl,...) what's in the  cert-chain, are the  certificate trusted ?

I like using guntls-cli since it display all  certificates in the path and provides the final trust outcome.

e.g

macintosh:~ kfelix$ gnutls-cli www.wwt.com

Processed 214 CA certificate(s).

Resolving 'www.wwt.com'...

Connecting to '198.200.139.195:443'...

- Certificate type: X.509

- Got a certificate list of 2 certificates.

- Certificate[0] info:

 - subject `C=US,ST=Missouri,L=Maryland Heights,O=World Wide Technology Holding Co.\, Inc.,OU=IT Operations,CN=*.wwt.com', issuer `C=US,O=GeoTrust Inc.,CN=GeoTrust SSL CA - G3', RSA key 2048 bits, signed using RSA-SHA256, activated `2015-02-10 00:00:00 UTC', expires `2017-05-11 23:59:59 UTC', SHA-1 fingerprint `c76d3b32cc494bef2f4950740ff94fb6e17e8fe9'

Public Key ID:

a8931554e42f5be923b093c0695a79f03e3e863e

Public key's random art:

+--[ RSA 2048]----+

|      .oo        |

|     . .         |

|    . . .        |

|   . = o . .     |

|    B * S +      |

|   + B + =       |

|  . +.* o o      |

|    Eooo . .     |

|   ..o..         |

+-----------------+

- Certificate[1] info:

 - subject `C=US,O=GeoTrust Inc.,CN=GeoTrust SSL CA - G3', issuer `C=US,O=GeoTrust Inc.,CN=GeoTrust Global CA', RSA key 2048 bits, signed using RSA-SHA256, activated `2013-11-05 21:36:50 UTC', expires `2022-05-20 21:36:50 UTC', SHA-1 fingerprint `5aeaee3f7f2a9449cebafeec68fdd184f20124a7'

- Status: The certificate is trusted. 

- Description: (TLS1.2)-(ECDHE-RSA-SECP256R1)-(AES-256-GCM)

- Session ID: 92:C8:94:E2:E6:0D:09:C6:7B:90:00:24:4F:55:B0:4D:4A:B9:94:C1:60:DA:70:E6:98:2C:D0:AC:1E:E5:00:5F

- Ephemeral EC Diffie-Hellman parameters

 - Using curve: SECP256R1

 - Curve size: 256 bits

- Version: TLS1.2

- Key Exchange: ECDHE-RSA

- Server Signature: RSA-SHA256

- Cipher: AES-256-GCM

- MAC: AEAD

- Compression: NULL

- Options: safe renegotiation,

- Handshake was completed

- Simple Client Mode:

vrs a error

- Status: The certificate is NOT trusted. The name in the certificate does not match the expected. 

*** PKI verification of server certificate failed...

*** Fatal error: Error in the certificate.

*** Handshake has failed

GnuTLS error: Error in the certificate.

This will eliminate any funky thing with a browser and it's trust or policy, cache,etc.......

Use something like  ( gnu-tbs )  and follow the evidence, if you want to eliminate the FGT, set a fwpolicy b4 and to the site(s) in question and before and SSL intercept  fwpolicy

Don't make assumptions, don't  assume ,and follow the evidence.

;)

ken

[emnoc · Accepted solution]

Don't know about  window but do some  google search. On curl and SSL inspection, run  curl in  verbose mode and see what certs are shown

e.g

Macintosh:~ kfelix$ curl -v -k [link]https://www.giustizia.it:443[/link]

* Rebuilt URL to: [link]https://www.giustizia.it:443/[/link]

*   Trying 193.109.206.10...

* Connected to www.giustizia.it (193.109.206.10) port 443 (#0)

* TLS 1.2 connection using TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256

* Server certificate: *.giustizia.it

* Server certificate: GeoTrust SSL CA - G3

* Server certificate: GeoTrust Global CA

> GET / HTTP/1.1

> Host: www.giustizia.it

> User-Agent: curl/7.43.0

> Accept: */*

> 

< HTTP/1.1 301 Moved Permanently

< Server: nginx

< Date: Sun, 18 Sep 2016 03:40:42 GMT

< Content-Type: text/html

< Transfer-Encoding: chunked

< Connection: keep-alive

< Keep-Alive: timeout=20

< Location: [link]https://www.giustizia.it/giustizia[/link]

< X-Frame-Options: SAMEORIGIN

< X-Content-Type-Options: nosniff

< X-XSS-Protection: 1; mode=block

< X-Frame-Options: DENY

< Strict-Transport-Security: max-age=31536000; includeSubDomains

< 

<html>

<head><title>301 Moved Permanently</title></head>

<body bgcolor="white">

<center><h1>301 Moved Permanently</h1></center>

<hr><center>nginx</center>

</body>

</html>

* Connection #0 to host www.giustizia.it left intact

Guntls provide more details and the certificate in the  chain.  if your inspecting MiTM, the ssl-proxy cert should be present and trusted.

[emnoc]

This is a  ssl issues and web filter rule is not going to make a difference

"Cannot create secure connection"

Qs:  Do you have the  certificate from  the ssl-proxy accepted in the client?

Q: Does a MSIE or Safari browser  exhibits the same issue?

Q:what fortiOS version 

You can't just enable    SSL inspection without  understanding what's happening.

[CÃ_sar_Romero]

My friend,

That's a common problem with new versions of browsers, they already have installed certificates from some sites, making inaccessible the portal with no option to just skip the security alert.

The possible options in this case are replacing SSL Proxy certificate with one that will satisfy the security requirements of the application, or creating exempts for SSL Inspections on Policy & Objects > SSL Inspection.

Regards.

[Jack_T]

César Romero wrote:

My friend,

That's a common problem with new versions of browsers, they already have installed certificates from some sites, making inaccessible the portal with no option to just skip the security alert.

The possible options in this case are replacing SSL Proxy certificate with one that will satisfy the security requirements of the application, or creating exempts for SSL Inspections on Policy & Objects > SSL Inspection.

Regards.

Hi, I have not exempts under SSL inspections options, maybe I have an old version of fortiOS? Thanks! :)

[CÃ_sar_Romero · Accepted solution]

Jack_T wrote:

Hi, I have not exempts under SSL inspections options, maybe I have an old version of fortiOS? Thanks! :)

Exactly, this is available since FortiOS 5.2.

[Jack_T]

Ok, so I should update fortiOS. With upgrade I loose my configuration? If something goes wrog can I revert back changes?

Thanks in advance

[CÃ_sar_Romero · Accepted solution]

If you don't want problems just follow the Upgrade Path available in the release notes (available at the version folder in support.fortinet.com). In that case you won't lose any configuration.

Regards.

[MikePruett]

More recent browsers use something called HSTS (HTTP Strict Transport Security).

They are smart enough to cache certificates that way if someone jumps in the middle after the fact they will be alerted.

That may be the cause of your problem.

[Jack_T]

MikePruett wrote:

More recent browsers use something called HSTS (HTTP Strict Transport Security).

They are smart enough to cache certificates that way if someone jumps in the middle after the fact they will be alerted.

That may be the cause of your problem.

So how can I solve the problem without upgrading the firewall?

[MikePruett]

http://classically.me/blogs/how-clear-hsts-settings-major-browsers

This is a browser issue not a FortiGate issue btw....