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[[Category:OPS335]][[Category:OPS335 Labs]]
=== Online Resources===
* [https://en.wikipedia.org/wiki/Transport_Layer_Security TSL, SSL Definition]
* [https://www.e-rave.nl/create-a-self-signed-ssl-key-for-postfix Create a self signed SSL key for Postfix]
* [http://wiki2.dovecot.org/SSL/DovecotConfiguration Dovecot SSL configuration]
== INVESTIGATION 1: GENERATING A SELF-SIGNED CERTIFICATE ==
According to Wikipedia (https://en.wikipedia.org/wiki/Transport_Layer_Security), '''Transport Layer Security''' (TLS) and its predecessor, '''Secure Sockets Layer''' (SSL), both of which are frequently referred to as 'SSL', are cryptographic protocols designed to provide communications security over a computer network.
Normally (in production), you would need to pay a "certificate authority" to issue a '''certificate''' for you. That is essentially '''a "signed" public key''' that will tell strangers on the internet that your server is really yours (i.e. the certificate authority says so). There is an obvious problem with the previous statement but that is mainly how public key encryption works on the Internet today.
We will be generating our own public keys, mainly in order to avoid paying for a certificate. We will not have enough time to get into the details of what all the following commands do in this section. They are from [https://www.e-rave.nl/create-a-self-signed-ssl-key-for-postfix this blog post]. If you don't understand what the blog post refers to but would like to understand in more details, a good recommended book for interest, called Crypto by Steven Levy, provides a more in-depth discussion of encryption and security.
The public key cryptography concepts in this lab are the same in a previous lab ([http://zenit.senecac.on.ca/wiki/index.php/OPS335_Lab_1#SSH_Keys Lab1: SSH]), although the terminology is slightly different.
A simple way to summarize the differences is:
:* The '''.key''' file is your private key.
:* The '''.crt''' file is your public key.
=== Encrypting Postfix with Transport Layer Security (TLS) ===
'''Perform the following steps:'''
#Let's start with the "sending" SMTP server we have on VM2. Run the following, replacing <u>andrewsmith.org</u> with '''<u>your</u> domain name''':
<source lang="bash">mkdir -p /root/postfix-keys /etc/ssl/{private,certs}
cd /root/postfix-keys
openssl genrsa -des3 -out vm2.andrewsmith.org.key 2048
chmod 600 vm2.andrewsmith.org.key
openssl req -new -key vm2.andrewsmith.org.key -out vm2.andrewsmith.org.csr
openssl x509 -req -days 365 -in vm2.andrewsmith.org.csr -signkey vm2.andrewsmith.org.key -out vm2.andrewsmith.org.crt
openssl rsa -in vm2.andrewsmith.org.key -out vm2.andrewsmith.org.key.nopass
mv vm2.andrewsmith.org.key.nopass vm2.andrewsmith.org.key
openssl req -new -x509 -extensions v3_ca -keyout cakey.pem -out cacert.pem -days 3650
chmod 600 vm2.andrewsmith.org.key cakey.pem
cp vm2.andrewsmith.org.key cakey.pem /etc/ssl/private
cp vm2.andrewsmith.org.crt cacert.pem /etc/ssl/certs</source>
::'''NOTE:''' Those commands will create a certificate, a certificate signing request, a certificate authority, and sign your certificate with your certificate authority.<br>This would be the same as in the real world except there you would contact a real CA, here you're making up your own.
<ol><li value="2">Now, configure Postfix to use the generated certificate, by adding the following to your '''main.cf''' file:</li></ol>
<pre># Settings to enable secure SMTP using my self-signed certificate:
smtpd_tls_auth_only = no
smtpd_use_tls = yes
smtp_use_tls = yes
smtpd_tls_key_file = /etc/ssl/private/vm2.andrewsmith.org.key
smtpd_tls_cert_file = /etc/ssl/certs/vm2.andrewsmith.org.crt
smtpd_tls_CAfile = /etc/ssl/certs/cacert.pem
tls_random_source = dev:/dev/urandom
smtpd_tls_loglevel = 1</pre>
=== Setting Up and Testing Encryption with Thunderbird ===
'''Perform the following steps:'''
#Currently your Thunderbird is set up to use '''vm2.yoursenecaid.org''' for an SMTP server, with <u>no</u> security. Change that to use '''STARTTLS''' instead (you can change it under '''account settings --> Outgoing Server''').
# We haven't set up any user authentication, just an encrypted channel;therefore, leave the '''authentication method''' at the value: '''none'''.
#When you try to send an email Thunderbird will warn you about the self-signed certificate. You obviously know it's your certificate so you can tell Thunderbird to trust it:
[[Image:SMTP-certificate-warning.png]]
::'''NOTE:''' Your message may look slightly different (This author, that created the diagram above, made a little mistake when generating the certificate).
<ol><li value="4">After you confirm that security exception, send another email to yourself and make sure you receive it.</li><li> Notice that from the user's point of view nothing is different. But if you were an evildoer trying to steal an identity (the difference is huge). Before it was trivial and now it's computationally prohibitive.</li></ol>
=== Encryption Dovecot with Secure Socket layer (SSL) ===
Now we will ensure that our '''Dovecot''' connection is secure, and enforce that policy. With SMTP, you will need to allow plain text connections since that is the only method to pass email from server-to-server. With IMAP, there is no server-to-server interaction, but rather only client-to-server interaction. The reason to have an unencrypted IMAP connection would be if your '''IMAP server''' and '''IMAP client''' were the <u>same</u> machine.
'''Perform the following steps:'''
# Let's start by generating a new certificate for Dovecot on your vm3 machine by issuing the following commands:
<source lang="bash">mkdir /etc/ssl/{private,certs}
openssl genrsa -des3 -out vm3.andrewsmith.org.key 2048
chmod 600 vm3.andrewsmith.org.key
openssl req -new -key vm3.andrewsmith.org.key -out vm3.andrewsmith.org.csr
openssl x509 -req -days 365 -in vm3.andrewsmith.org.csr -signkey vm3.andrewsmith.org.key -out vm3.andrewsmith.org.crt
openssl rsa -in vm3.andrewsmith.org.key -out vm3.andrewsmith.org.key.nopass
mv vm3.andrewsmith.org.key.nopass vm3.andrewsmith.org.key
openssl req -new -x509 -extensions v3_ca -keyout cakey.pem -out cacert.pem -days 3650
chmod 600 vm3.andrewsmith.org.key cakey.pem
cp vm3.andrewsmith.org.key cakey.pem /etc/ssl/private
cp vm3.andrewsmith.org.crt cacert.pem /etc/ssl/certs</source>
::'''NOTE:''' This process is identical to what you've done for the vm2 certificate. In fact if your IMAP and SMTP servers are on the same machine you can share the certificate between them. In our case, they are not on the same machine.
<ol><li value="2">Next, we need to configure Dovecot to use this for encrypted connections and not allow any kind of plain text connections. Edit the '''10-auth.conf''', <u>and</u> '''10-ssl.conf''' files and change the following settings (note: these parameters already exist in those files, just find them and set them to the correct value):</li></ol>
<source lang="bash">ssl = required
ssl_cert = <path_to_your_crt_file
ssl_key = <path_to_your_key_file
disable_plaintext_auth = yes
</source>
<ol><li value="3">Now, we will disable normal imap connections, leaving only imaps (secured imap) allowed. Edit the '''10-master.conf''' file and set the port number in '''inet_listener imap''' to '''0'''.</li>
<li>Your key/certificate doesn't have a '''.pem''' extension but they are PEM-encoded files. You can confirm that using the '''file''' command. If you're interested, learning more about configuring Dovecot for SSL, refer to the following documentation: [http://wiki2.dovecot.org/SSL/DovecotConfiguration Dovecot SSL configuration].</li></ol>
=== Verifying that Mail Messages are Encrypted===
'''Perform the following steps:'''
#Use the '''ss''' command to confirm you're only listening on the '''imaps''' port, and not the plain imap port.
#Next, reconfigure your account settings in Thunderbird to use the '''SSL/TLS''' connection security with your IMAP server, leaving the password as '''Normal Password'''.
|- valign== INVESTIGATION 3: ADDING THE OTHER VMS ==*When you have successfully made this change on '''vm3''', repeat these steps so that '''vm1''' will also use NIS for user identification from files located on '''vm2'''.**Warning: When configuring the location of the NIS server to bind to, use the ip address instead of the hostname. When the machine is booting, you have no guarantee that '''named''' starts before '''ypbind'''."top"
|width="10%" | [[Image:Roundcube.png|thumb|right|200px|'''Roundcube''' webmail application Logo<br>GPL,<br> https://commons.wikimedia.org/w/index.php?curid=Completing 1772791]] |width="10%" |[[Image:roundcube-pic.png|thumb|right|300px|Screencapture of '''roundcube''' webmail application running in order to send and receive mail messages via a web-browser.]] |} In the investigation, we will simply install, configure and run the '''roundcube''' webmail application. '''Perform the following steps on vm1:''' *Perform a search on the roundcube application in order to access the website.*Either Download the "zipped tarball" from their website from a direct link or use the wget command to download directly from a download link (This part may take some effort depending on the Sourceforge website).*Extract the "zipped tarball" and rename the generated directory that contains download source code to: '''webmail'''.::* Use the '''--no-same-owner''' option when extracting the tar achive to ensure that the files do not keep the original owner (who will not exist on your system).*Change the Lab=ownership of the '''temp''' and '''logs''' directories so they belong to apache.*This service needs to be able to write to several directories ('''temp''' and '''logs''') that SELinux prevents write access to. If you are in a section that has SELinux set to '''enforcing''', run the following commands to let it know that apache should be allowed to write to files in those directories.<source lang="bash">semanage fcontext -a -t httpd_log_t '/var/www/html/webmail/temp(/.*)?'semanage fcontext -a -t httpd_log_t '/var/www/html/webmail/logs(/.*)?'restorecon -v -R /var/www/html/webmail</source>You ::*If your machine does not have the semage command, use yum to install the policycoreutils-python package.*In the directory now created an NIS named "webmail", there will be a file named '''INSTALL''' which will walk you through the rest of the Roundcube installation.<br /><br />Some installation tips to consider: ::* Be careful about copying & pasting the MySQL setup part: take time and pay attention to detail: do not try to "rush it".::* You will need to install additional Apache modules including: '''php-xml''' and '''php-mbstring'''.::* Don't forget to set the password in the roundcube configuration. *Note that both of your IMAP and SMTP servers are on different machines (i.e. not on vm1). Therefore, you will need to set the following options for Roundcube: ::* '''$config['smtp_server']'''::* '''$config['default_host']'''::* '''$config['default_port']''' :::'''NOTE:''' The last <u>two</u> entries above refer to your IMAP server for *You should be able to test the configuration in your network Roundcube installer after completing Step 3.</li><li>Try to test if the roundcube webmail application is working by sending and caused receiving e-mail messages.* {{Admon/important |Backup your other virtual machines VMs!|You MUST perform a '''full backup''' of ALL of your VMs whenever you complete your '''OPS335 labs''' or when working on your '''OPS335 assignments'''. You should be using the dump command, and you should use the Bash shell script that you were adviced to create in order to use it as a central repository for user informationbackup all of your VMs.}} '''Record steps, commands, and your observations on this investigation in your OPS335 lab log-book''' ==COMPLETING THE LAB==In completing this lab you have gained experience...
'''Depending on your professor you will either be asked to submit the lab in class, or online. Follow the appropriate set of instructions below.'''
===Online Submission(Peter Callaghan's Classes only)===Follow the instructions for lab 7 8 on moodle.
===In Class Submission===
'''Arrange evidence (command output) for each of these items on your screen, then ask your instructor to review them and sign off on the lab's completion:'''
::<span style="color:green;font-size:1.5em;">✓</span> To be completed Thunderbird with a message sent and received using encrypted channels.::<span style="color:green;font-size:1.5em;">✓</span>New Thunderbird server configuration for your account.::<span style="color:green;font-size:1.5em;">✓</span>Logs on vm2 and vm3 showing the message has been sent and received.::<span style="color:green;font-size:1.5em;">✓</span>Your webmail showing your inbox::<span style="color:green;font-size:1.5em;">✓</span>Your webmail sending an email out::<span style="color:green;font-size:1.5em;">✓</span>You receiving that mail on an exernal account::<span style="color:green;font-size:1.5em;">✓</span>Download the labcheck8.bash checking bash shell script by an issuing the command:<br><br>'''wget http://matrix.senecac.on.ca/~peter.callaghan/files/OPS335/labcheck8.bash'''<br><br>set execute permission and run the shell script on your '''c7host''' machine. ::*For '''Peter's classes''', follow his Online Submission instructions in Moodle.::*For '''Murray's classes''', run command (piping to the '''more''' command) and show output to instructor who uses in class submission.::<span style="color:green;font-size:1.5em;">✓</span>Completed Lab8 log-book notes. ==EXPLORATION QUESTIONS==
