Making a Linux Plesk 8.6 Server PCI Compliant

Posted on Mar 19, 2010

To make a server that is running Plesk PCI compliant follow these steps:

Turn off medium and weak ciphers on the Plesk port (8443). This is done by editing the /usr/local/psa/admin/conf/httpsd.custom.include file.

SSLProtocol -ALL +SSLv3 +TLSv1
SSLCipherSuite HIGH:!MEDIUM:!LOW:!SSLv2:!EXP:!NULL:@STRENGTH
ErrorDocument 417 "Expect not supported"
ErrorDocument 413 "Request Entity Too Large."
ServerTokens Prod
UserDir Disabled

The ErrorDocument prevents a XSS exploit using the expect headers. This must be done in the httpsd.custom.include file or else you Plesk will over write the changes. For the changes to take affect:



    /sbin/service psa stop
    /sbin/service psa start

To test and make sure SSLv2 is disabled:



    openssl s_client -connect localhost:8443 -ssl2

You should not see any SSL information. To test the Expect headers:



    openssl s_client -host localhost:8443

Once you see a ‘—’ enter the following to test:
R

....snip...
Get / HTTP/1.1
Host: localhost
Expect: */&lt;script&gt;fooz&lt;/script&gt;/*

If everything worked, you will see:

HTTP/1.1 417 Expectation Failed
Date: Wed, 24 Mar 2010 21:08:32 GMT
Server: Apache
Transfer-Encoding: chunked
Content-Type: text/html; charset=iso-8859-1
15
Expect not supported
0

Do the same thing as you did above for Apache. Create the file /etc/httpd/conf.d/zz050-psa-disable-weak-ssl-ciphers.conf and add:
```
SSLProtocol -ALL +SSLv3 +TLSv1
SSLCipherSuite HIGH:!MEDIUM:!SSLv2:!LOW:!EXP:!aNULL:@STRENGTH
```
Apache has to be restarted for the changes to take affect:
```
    /sbin/service httpd restart
    
```
To test and make sure SSLv2 is disabled:
```
    openssl s_client -connect localhost:443 -ssl2
    
```
You should not see any SSL information.
Moving on to IMAP and POP3, the /etc/courier-imap/imapd-ssl and /etc/courier-imap/pop3d-ssl files need to be modified by adding the following line:
```
TLS_CIPHER_LIST="HIGH:!ADH:RC4+RSA:!SSLv2:!LOW:!MEDIUM:@STRENGTH"
```
If there is another line with that variable setting, make sure you either remove it or comment it out. Restart the service:
```
    /sbin/service courier-imap restart
    
```
Test to make sure that SSLv2 has been properly disabled:
```
    openssl s_client -connect localhost:993 -ssl2
    openssl s_client -connect localhost:995 -ssl2
    
```
You should not see any SSL information.
Turn off SSLv2 for port 465, add the following line to /var/qmail/control/tlsserverciphers and /var/qmail/control/tlsclientciphers
```
!ALL:!aNULL:!ADH:!eNULL:!LOW:!EXP:!SSLv2:RC4+RSA:+HIGH:!MEDIUM
```
Restart qmail:
```
    /sbin/service qmail restart
    
```
Test the new settings:
```
    openssl s_client -connect  localhost:465 -ssl2
    
```
You should not see any SSL information.
Configure named that it does not support recursion. This is done by editing the /etc/named.conf and adding the following below the options section
```
recursion no;
```
PCI audits will fail if the certificate has expired for courier-imap. This is easily fixed. Navigate to the /usr/share/courier-imap directory and run the following commands:
```
    ./mkimapdcert
    ./mkpop3dcert
    
```
This will create a new certificate for both services resolving the issue of expired certificates. These certificates will expire in 1 year.
Add the following to your /etc/php.ini and your /usr/local/psa/admin/conf/php.ini, this requires httpd and Plesk to be restarted:
```
expose_php = Off
```
```
    /sbin/service httpd restart
    /sbin/service psa restart
    
```

PCI scans are starting to fail when connecting to a site via port 25 (SMTP) and 587 (submission). There is another certificate that needs to be updated. I used a self signed certificate, but you can replace the certificate with one from a respected CA:



    cd /var/qmail/control
    openssl genrsa 2048 > host.key
    openssl req -new -x509 -nodes -sha1 -days 730 -key host.key > host.cert
    cat host.cert host.key > host.pem
    cp servercert.pem > servercert.pem.bk
    mv host.pem servercert.pem
    /sbin/service qmail restart

To test:



    openssl s_client -connect host.com:25 -starttls smtp
    openssl s_client -connect host.com:587 -starttls smtp

This has been written and tested on Plesk 8.6 Some of the items may be applied to later versions of Plesk