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[[Category:OPS335]][[Category:OPS335 Labs]]
==OBJECTIVE & PREPARATION==
[[Image:Email-servers.png]]
:: If e-mail traffic on a LAN was not encrypted, it would be easy and inexpensive to intercept (in order to obtain your username and password). These days, unencrypted connections from your client to your SMTP/IMAP/POP3 server very rarely exist. You see in our diagram that one of the SMTP connections is supposed to be encrypted (this is the one that would be "LAN" traffic) and the IMAP connection as well (this one is either LAN-like traffic or is connecting to localhost, which is a different scenario altogether). We're going to secure the two connections that we left to be in plain text previously. Unfortunately encrypting things is rarely a straighforward process. Fortunately we have a whole week to spend on it. === 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-keysopenssl genrsa -des3 -out vm2.andrewsmith.org.key 2048chmod 600 vm2.andrewsmith.org.keyopenssl req -new -key vm2.andrewsmith.org.key -out vm2.andrewsmith.org.csropenssl x509 -req -days 365 -in vm2.andrewsmith.org.csr -signkey vm2.andrewsmith.org.key -out vm2.andrewsmith.org.crtopenssl rsa -in vm2.andrewsmith.org.key -out vm2.andrewsmith.org.key.nopassmv vm2.andrewsmith.org.key.nopass vm2.andrewsmith.org.keyopenssl req -new -x509 -extensions v3_ca -keyout cakey.pem -out cacert.pem -days 3650chmod 600 vm2.andrewsmith.org.key cakey.pemcp vm2.andrewsmith.org.key cakey.pem /etc/ssl/privatecp 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=Completing "2">Now, configure Postfix to use the Labgenerated 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 = nosmtpd_use_tls = yessmtp_use_tls = yessmtpd_tls_key_file = /etc/ssl/private/vm2.andrewsmith.org.keysmtpd_tls_cert_file = /etc/ssl/certs/vm2.andrewsmith.org.crtsmtpd_tls_CAfile = /etc/ssl/certs/cacert.pemtls_random_source = dev:/dev/urandomsmtpd_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 now created an NIS 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 2048chmod 600 vm3.andrewsmith.org.keyopenssl req -new -key vm3.andrewsmith.org.key -out vm3.andrewsmith.org.csropenssl x509 -req -days 365 -in vm3.andrewsmith.org.csr -signkey vm3.andrewsmith.org.key -out vm3.andrewsmith.org.crtopenssl rsa -in vm3.andrewsmith.org.key -out vm3.andrewsmith.org.key.nopassmv vm3.andrewsmith.org.key.nopass vm3.andrewsmith.org.keyopenssl req -new -x509 -extensions v3_ca -keyout cakey.pem -out cacert.pem -days 3650chmod 600 vm3.andrewsmith.org.key cakey.pemcp vm3.andrewsmith.org.key cakey.pem /etc/ssl/privatecp 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 = requiredssl_cert = <path_to_your_crt_filessl_key = <path_to_your_key_filedisable_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 network account settings in Thunderbird to use the '''SSL/TLS''' connection security with your IMAP server, leaving the password as '''Normal Password'''. ::'''NOTE:''' When you send your test email, you will get another warning because you're using a self-signed certificate on '''vm3'''. Make certain to authorize the exception. '''Record steps, commands, and caused your other virtual machines observations on this investigation in your OPS335 lab log-book''' == INVESTIGATION 2: INSTALL, CONFIGURE & RUN WEBMAIL APPLICATION (Roundcube Mail) =={|cellpadding="15" width="40%" align="right" |- valign="top" |width="10%" | [[Image:Roundcube.png|thumb|right|200px|'''Roundcube''' webmail application Logo<br>GPL,<br> https://commons.wikimedia.org/w/index.php?curid=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 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 as 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>::*If your machine does not have the semage command, use yum to install the policycoreutils-python package.*In the directory now named "webmail", there will be a central repository 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 user informationRoundcube: ::* '''$config['smtp_server']'''::* '''$config['default_host']'''::* '''$config['default_port']''' :::'''NOTE:''' The last <u>two</u> entries above refer to your IMAP server *You should be able to test the configuration in your Roundcube installer after completing Step 3.</li><li>Try to test if the roundcube webmail application is working by sending and receiving e-mail messages.* {{Admon/important |Backup your 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 backup 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==
