Matteo Mattei

Hello, my name is Matteo Mattei and this is my personal website. I am computer engineer with a long experience in Linux system administration and web software development.

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Client and server SSL mutual authentication with NodeJs

In order to communicate securely between server and client it is important not only to cipher the channel but also trust both endpoints. To do this, a common practice is to do mutual authentication between client and server.

In this post I show you how to implement mutual authentication in Nodejs.

Assume we want to create a mutual authentication channel between a server running on server.aaa.com and a client running on client.bbb.com. Keep in mind the domain names because they are important in the certificates creation.

First of all we need to generate certificates. Obviously you can use certificates released by any certification authority but for the purpose of the article I am going to create self signed certificates and related CA.

Step 1: Create a working folder and setup hosts file

// AS USER
$ mkdir ~/mutual_authentication_example
$ cd ~/mutual_authentication_example

// AS ROOT
# echo '127.0.0.1 server.aaa.com' >> /etc/hosts
# echo '127.0.0.1 client.bbb.com' >> /etc/hosts

Step 2: Generate server certificates

We are going to create a Certification Authority (CA) certificate for the server with 1 year validity and the related key.

$ openssl req -new -x509 -days 365 -keyout server-ca-key.pem -out server-ca-crt.pem
Generating a RSA private key
...........................................................................................+++++
.......................................+++++
writing new private key to 'ca-key.pem'
Enter PEM pass phrase:
Verifying - Enter PEM pass phrase:
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:IT
State or Province Name (full name) [Some-State]:Florence
Locality Name (eg, city) []:Campi Bisenzio
Organization Name (eg, company) [Internet Widgits Pty Ltd]:AAA Ltd
Organizational Unit Name (eg, section) []:DevOps
Common Name (e.g. server FQDN or YOUR name) []:aaa.com
Email Address []:info@aaa.com

The PEM pass phrase is optional. The other questions are not mandatory but it’s better if you answer all. The most important question is the Common Name which should be the server main domain (aaa.com).

Now we generate the actual server certificate which will be used in the ssl handshake. First of all we have to generate a random key (4096 bit length in our example):

$ openssl genrsa -out server-key.pem 4096
Generating RSA private key, 4096 bit long modulus (2 primes)
.........++++
...................++++
e is 65537 (0x010001)

Then generate a Certificate Signing Request (CSR) with the key we have generated:

$ openssl req -new -sha256 -key server-key.pem -out server-csr.pem
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:IT
State or Province Name (full name) [Some-State]:Florence
Locality Name (eg, city) []:Campi Bisenzio
Organization Name (eg, company) [Internet Widgits Pty Ltd]:AAA Ltd
Organizational Unit Name (eg, section) []:DevOps
Common Name (e.g. server FQDN or YOUR name) []:server.aaa.com
Email Address []:info@aaa.com

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:

Pay attention to the Common Name which must have the same name of the host will serve the application (server.aaa.com). As final step, generate the server certificate (validity 1 year) from the CSR previously created and sign it with the CA key:

$ openssl x509 -req -days 365 -in server-csr.pem -CA server-ca-crt.pem -CAkey server-ca-key.pem -CAcreateserial -out server-crt.pem
Signature ok
subject=C = IT, ST = Florence, L = Campi Bisenzio, O = AAA Ltd, OU = DevOps, CN = server.aaa.com, emailAddress = info@aaa.com
Getting CA Private Key
Enter pass phrase for server-ca-key.pem:

The password requested is the one inserted during CA key generation. To verify the certificate signature against the CA you can issue the following command:

$ openssl verify -CAfile server-ca-crt.pem server-crt.pem
server-crt.pem: OK

Now we have all the server certificates we need!

-rw-rw-r--  1 matteo matteo 1440 dic 26 12:52 server-ca-crt.pem
-rw-rw-r--  1 matteo matteo   41 dic 26 17:48 server-ca-crt.srl
-rw-------  1 matteo matteo 1854 dic 26 12:51 server-ca-key.pem
-rw-rw-r--  1 matteo matteo 1671 dic 26 17:48 server-crt.pem
-rw-rw-r--  1 matteo matteo 1785 dic 26 17:34 server-csr.pem
-rw-------  1 matteo matteo 3243 dic 26 17:30 server-key.pem

Step 3: Generate client certificates

Now it’s time to do the same steps for the Client. First of all create a Certification Authority (CA) certificate for the client with 1 year validity and the related key.

$ openssl req -new -x509 -days 365 -keyout client-ca-key.pem -out client-ca-crt.pem
Generating a RSA private key
..........................................................+++++
.............................................+++++
writing new private key to 'client-ca-key.pem'
Enter PEM pass phrase:
Verifying - Enter PEM pass phrase:
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:IT
State or Province Name (full name) [Some-State]:Rome
Locality Name (eg, city) []:Rome
Organization Name (eg, company) [Internet Widgits Pty Ltd]:BBB Ltd
Organizational Unit Name (eg, section) []:
Common Name (e.g. server FQDN or YOUR name) []:bbb.com
Email Address []:info@bbb.com

The PEM pass phrase is optional. The other questions are not mandatory but it’s better if you answer all. The most important question is the Common Name which should be the client main domain (bbb.com).

Now we generate the actual client certificate which will be used in the ssl handshake. First of all we have to generate a random key (4096 bit length in our example):

$ openssl genrsa -out client-key.pem 4096
Generating RSA private key, 4096 bit long modulus (2 primes)
..............++++
........................................................................................++++
e is 65537 (0x010001)

Then generate a Certificate Signing Request (CSR) with the key we have generated:

$ openssl req -new -sha256 -key client-key.pem -out client-csr.pem
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:IT
State or Province Name (full name) [Some-State]:Rome
Locality Name (eg, city) []:Rome
Organization Name (eg, company) [Internet Widgits Pty Ltd]:BBB Ltd
Organizational Unit Name (eg, section) []:
Common Name (e.g. server FQDN or YOUR name) []:client.bbb.com
Email Address []:info@bbb.com

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:

Pay attention to the Common Name which must have the same name of the host will serve the application (client.bbb.com). As final step, generate the client certificate (validity 1 year) from the CSR previously created and sign it with the CA key:

$ openssl x509 -req -days 365 -in client-csr.pem -CA client-ca-crt.pem -CAkey client-ca-key.pem -CAcreateserial -out client-crt.pem
Signature ok
subject=C = IT, ST = Rome, L = Rome, O = BBB Ltd, CN = client.bbb.com, emailAddress = info@bbb.com
Getting CA Private Key
Enter pass phrase for client-ca-key.pem:

The password requested is the one inserted during CA key generation. To verify the certificate signature against the CA you can issue the following command:

$ openssl verify -CAfile client-ca-crt.pem client-crt.pem
client-crt.pem: OK

Now we have all the client certificates we need!

-rw-rw-r--  1 matteo matteo 1350 dic 26 17:59 client-ca-crt.pem
-rw-rw-r--  1 matteo matteo   41 dic 26 18:06 client-ca-crt.srl
-rw-------  1 matteo matteo 1854 dic 26 17:58 client-ca-key.pem
-rw-rw-r--  1 matteo matteo 1586 dic 26 18:06 client-crt.pem
-rw-rw-r--  1 matteo matteo 1712 dic 26 18:04 client-csr.pem
-rw-------  1 matteo matteo 3243 dic 26 18:03 client-key.pem

Step 4: Run the code!

Move all certificates in a folder called certs:

$ mkdir ~/mutual_authentication_example/certs
$ mv ~/mutual_authentication_example/*.pem ~/mutual_authentication_example/certs/
$ mv ~/mutual_authentication_example/*.srl ~/mutual_authentication_example/certs/

Now create a server.js application:

const fs = require("fs");
const https = require("https");
const options = {
  key: fs.readFileSync(`${__dirname}/certs/server-key.pem`),
  cert: fs.readFileSync(`${__dirname}/certs/server-crt.pem`),
  ca: [
    fs.readFileSync(`${__dirname}/certs/client-ca-crt.pem`)
  ],
  // Requesting the client to provide a certificate, to authenticate.
  requestCert: true,
  // As specified as "true", so no unauthenticated traffic
  // will make it to the specified route specified
  rejectUnauthorized: true
};
https
  .createServer(options, function(req, res) {
    console.log(
      new Date() +
        " " +
        req.connection.remoteAddress +
        " " +
        req.method +
        " " +
        req.url
    );
    res.writeHead(200);
    res.end("OK!\n");
  })
  .listen(8888);

Now create a client.js application:

const fs = require("fs");
const https = require("https");
const message = { msg: "Hello!" };

const req = https.request(
  {
    host: "server.aaa.com",
    port: 8888,
    secureProtocol: "TLSv1_2_method",
    key: fs.readFileSync(`${__dirname}/certs/client-key.pem`),
    cert: fs.readFileSync(`${__dirname}/certs/client-crt.pem`),
    ca: [
      fs.readFileSync(`${__dirname}/certs/server-ca-crt.pem`)
    ],
    path: "/",
    method: "GET",
    headers: {
      "Content-Type": "application/json",
      "Content-Length": Buffer.byteLength(JSON.stringify(message))
    }
  },
  function(response) {
    console.log("Response statusCode: ", response.statusCode);
    console.log("Response headers: ", response.headers);
    console.log(
      "Server Host Name: " + response.connection.getPeerCertificate().subject.CN
    );
    if (response.statusCode !== 200) {
      console.log(`Wrong status code`);
      return;
    }
    let rawData = "";
    response.on("data", function(data) {
      rawData += data;
    });
    response.on("end", function() {
      if (rawData.length > 0) {
        console.log(`Received message: ${rawData}`);
      }
      console.log(`TLS Connection closed!`);
      req.end();
      return;
    });
  }
);
req.on("socket", function(socket) {
  socket.on("secureConnect", function() {
    if (socket.authorized === false) {
      console.log(`SOCKET AUTH FAILED ${socket.authorizationError}`);
    }
    console.log("TLS Connection established successfully!");
  });
  socket.setTimeout(10000);
  socket.on("timeout", function() {
    console.log("TLS Socket Timeout!");
    req.end();
    return;
  });
});
req.on("error", function(err) {
  console.log(`TLS Socket ERROR (${err})`);
  req.end();
  return;
});
req.write(JSON.stringify(message));

It’s now time to test. Open a terminal and start the server:

$ node server.js

Open another terminal and run the client:

$ node client.js
TLS Connection established successfully!
Response statusCode:  200
Response headers:  {
  date: 'Sat, 26 Dec 2020 17:26:13 GMT',
  connection: 'close',
  'transfer-encoding': 'chunked'
}
Server Host Name: server.aaa.com
Received message: OK!

TLS Connection closed!

On the first terminal (the server) will be logged a new connection:

$ node server.js
Sat Dec 26 2020 18:26:13 GMT+0100 (Central European Standard Time) ::ffff:127.0.0.1 GET /

Conclusions

Basically you have to explicitly include the CA of the server in the connection object of the client and vice versa. In this way the server will be able to verify the client certificate and the client will be able to verify the server certificate.

I hope this example can help you implementing a mutual authentication between your endpoints in your applications. You can download demo files from this GitHub repository.


Show Git branch name on shell prompt

Maintaining multiple git repositories might became a mess specially if you often switch from one folder to another and if you are used to work on different branches. Basically you have to type every time git branch on the terminal to make sure to work on the correct working copy.

If your OS is Linux (or MacOSx) and you have Bash installed, you can customize the Bash prompt to always show the current branch name in your working directory.

First of all type ensure your default shell is /bin/bash

matteo@barracuda ~ $ echo $SHELL
/bin/bash

Then edit ~/.bashrc file and add the following lines at the bottom:

parse_git_branch() {
     git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1)/'
}

PS1="\u@\h \[\e[32m\]\w \[\e[91m\]\$(parse_git_branch)\[\e[00m\]$ "

Basically we added the parse_git_branch() function which prints out the current git branch (if you are in a git project) and then reset the PS1 variable (the Bash prompt) calling the previously function.

Now you have to enable the new configuration just typing the following or doing a new login:

matteo@barracuda ~ $ . ~/.bashrc

Let’s try and see how it looks like:

matteo@barracuda ~ $ cd src/myproject
matteo@barracuda ~/src/myproject (master)$

That’s all! If you like to change colors or other PS1 parameters you can refer to the following resources:


How to configure a secure SFTP chroot jail

If you have a linux server, openssh is almost always already present, so without any other tool you can configure a super secure SFTP chroot jail to allow your users to access the server limiting the visibility to their home directory.

Start creating a new linux system group called sftponly:

groupadd --system sftponly

We create a system group because we want an ID lower than 1000 so that every new user will take a sequential UID. Now open /etc/ssh/sshd_config and make sure to have the following lines:

PasswordAuthentication yes
ChallengeResponseAuthentication no

Now replace the line starting with Subsystem with the following:

Subsystem sftp internal-sftp

This line tells SSH to use its internal sftp subsytem to mange SFTP connections.

Now add the following lines at the bottom of the file:

Match Group sftponly
    ChrootDirectory %h
    X11Forwarding no
    AllowTcpForwarding no
    ForceCommand internal-sftp

Basically the above section describes how to handle connections from users belonging to sftponly group. In particular we are telling SSH to chroot the users to their home directory, does not allow X11 and TCP forwarding and force to use the internal sftp interface.

After do that, restart ssh server to make the changes active:

/etc/init.d/ssh restart

Now the SFTP server is ready to be used but you must keep in mind some important rules otherwise it will not work!

  1. every user home directory must belong to root:root
  2. every user home directory must have 0755 permissions
  3. every user must belong to sftponly group
  4. every first level folder in user home directory must belong to ${USER}:sftponly

Let’s do an example: create a new user matteo with no login shell, assign it to sftpgroup group and set a password:

useradd --create-home --shell /usr/sbin/nologin --user-group matteo
usermod --groups sftponly matteo
passwd matteo

Assuming you want the following permissions:

mkdir /home/matteo/pics    # write access by user matteo
mkdir /home/matteo/musics  # write access by user matteo
mkdir /home/matteo/logs    # read only access by user matteo

Configure the folders in this way:

chown root:root /home/matteo
chmod 755 /home/matteo
chown matteo:sftponly /home/matteo/pics
chown matteo:sftponly /home/matteo/musics
chown matteo:sftponly /home/matteo/logs
chmod 555 /home/matteo/logs

Now try with sftp command line client or with filezilla and test your new SFTP server. Files created from an SFTP session will belong to matteo:matteo.

As you can understand, this configuration is very useful for web servers running with PHP-FPM where every VirtualHost runs with its own user and privileges, so you can restrict the access by user with a secure SFTP connection and at the same time avoid all the problems related to the files permissions management and the configuration of a separated FTP/FTPS server.

I hope you enjoy this article. If you like it please leave a comment!


Monitor SSH access and send email when someone logins

In order to monitor SSH access we can rely on rsyslog given all SSH accesses are recorded in /var/log/auth.log. Start creating a custom rsyslog configuration /etc/rsyslog.d/90-ssh.conf with the following content:

Basically we are telling rsyslog to look for lines where the program name is sshd and the message contains the session opened for user. Every time the above condition is matched, rsyslog will call the script we are going to create passing the entire log line as parameter.

Assuming we want to receive an email with the user that have been logged, open your editor and create the file /usr/local/bin/log_access.py:

Make the file executable:

chmod +x /usr/local/bin/log_access.py

Remember to fill the SMTP data at the beginning of the script. As you can see the above script also logs all logins to /var/log/logins.log.

Feel free to do what you want in the python script, the above it’s only an example!

Now restart rsyslog and try if everything works as expected.

/etc/init.d/rsyslog restart

Let me know your work cases and if this article can help you!


Full web server setup with Debian 10 (Buster)

Setup bash and update the system

cp /etc/skel/.bashrc /root/.bashrc
apt-get update
apt-get dist-upgrade

Configure hostname correctly

Make sure to have the following two lines (with the same format) at the top of your /etc/hosts file

127.0.0.1       localhost.localdomain localhost
xxx.xxx.xxx.xxx web1.myserver.com web1

Note: xxx.xxx.xxx.xxx is the public IP address assigned to your server.

Install all needed packages

apt install wget vim git acl screen rsync net-tools pwgen php mariadb-server mariadb-client apache2 iptables shorewall php php-cli php-curl php-dev php-gd php-imagick php-imap php-memcache php-pspell php-recode php-tidy php-xmlrpc php-pear php-fpm php-mbstring php-mysql postfix ca-certificates bsd-mailx

Postfix:

  • Select Internet Site
  • System mail name: (insert here the FQDN, for example web1.myserver.com)

Setup chrooted SFTP jail

Create sftponly group:

addgroup --system sftponly

Edit /etc/ssh/sshd_config and make sure to have the following lines:

PasswordAuthentication yes
ChallengeResponseAuthentication no

Then change the Subsystem line with the following:

Subsystem sftp internal-sftp

And create the section to allow chrooted SFTP access to the users belonging to the sftponly group.

Match Group sftponly
    ChrootDirectory %h
    X11Forwarding no
    AllowTcpForwarding no
    ForceCommand internal-sftp

Now restart ssh server:

/etc/init.d/sshd restart

In order to have a working sftp jail, there are 4 rules to follow:

  1. every user home directory must belong to root:root
  2. every user home directory must have 0755 permissions
  3. every user must belong to sftponly group
  4. every subfolder in user home directory must belong to ${USER}:sftponly

Setup Apache

Stop Apache web server:

/etc/init.d/apache2 stop

Backup Apache configuration:

cp /etc/apache2/apache2.conf /etc/apache2/apache2.conf.backup

Edit the following lines in /etc/apache2/apache2.conf

  • From Timeout 300 to Timeout 45
  • From KeepAliveTimeout 5 to KeepAliveTimeout 15

Create a configuration for phpmyadmin:

cat << EOF > /etc/apache2/conf-available/phpmyadmin.conf
Alias /phpmyadmin /usr/share/phpmyadmin

<Directory /usr/share/phpmyadmin>
    Options SymLinksIfOwnerMatch
    DirectoryIndex index.php

    <IfModule mod_php5.c>
        <IfModule mod_mime.c>
            AddType application/x-httpd-php .php
        </IfModule>
        <FilesMatch ".+\.php$">
            SetHandler application/x-httpd-php
        </FilesMatch>

        php_value include_path .
        php_admin_value upload_tmp_dir /var/lib/phpmyadmin/tmp
        php_admin_value open_basedir /usr/share/phpmyadmin/:/etc/phpmyadmin/:/var/lib/phpmyadmin/:/usr/share/php/php-gettext/:/usr/share/php/php-php-gettext/:/usr/share/javascript/:/usr/share/php/tcpdf/:/usr/share/doc/phpmyadmin/:/usr/share/php/phpseclib/
        php_admin_value mbstring.func_overload 0
    </IfModule>
    <IfModule mod_php.c>
        <IfModule mod_mime.c>
            AddType application/x-httpd-php .php
        </IfModule>
        <FilesMatch ".+\.php$">
            SetHandler application/x-httpd-php
        </FilesMatch>

        php_value include_path .
        php_admin_value upload_tmp_dir /var/lib/phpmyadmin/tmp
        php_admin_value open_basedir /usr/share/phpmyadmin/:/etc/phpmyadmin/:/var/lib/phpmyadmin/:/usr/share/php/php-gettext/:/usr/share/php/php-php-gettext/:/usr/share/javascript/:/usr/share/php/tcpdf/:/usr/share/doc/phpmyadmin/:/usr/share/php/phpseclib/
        php_admin_value mbstring.func_overload 0
    </IfModule>

</Directory>

# Authorize for setup
<Directory /usr/share/phpmyadmin/setup>
    <IfModule mod_authz_core.c>
        <IfModule mod_authn_file.c>
            AuthType Basic
            AuthName "phpMyAdmin Setup"
            AuthUserFile /etc/phpmyadmin/htpasswd.setup
        </IfModule>
        Require valid-user
    </IfModule>
</Directory>

# Disallow web access to directories that don't need it
<Directory /usr/share/phpmyadmin/templates>
    Require all denied
</Directory>
<Directory /usr/share/phpmyadmin/libraries>
    Require all denied
</Directory>
<Directory /usr/share/phpmyadmin/setup/lib>
    Require all denied
</Directory>
EOF

Configure the proper Apache modules and configurations:

a2dismod mpm_worker
a2dismod mpm_prefork

a2enmod mpm_event
a2enmod ssl
a2enmod rewrite
a2enmod headers
a2enmod deflate
a2enmod proxy
a2enmod proxy_http
a2enmod proxy_fcgi
a2enmod http2
a2enmod setenvif

a2enconf security
a2enconf php7.3-fpm
a2enconf phpmyadmin

Now restart Apache:

/etc/init.d/apache2 restart

Setup MariaDB

Secure MariaDB installation:

mysql_secure_installation
  • Enter current password for root (enter for none): [ENTER]
  • Set root password? [Y/n] Y
  • Write your MARIAB_ROOT_PASSWORD
  • Remove anonymous users? [Y/n] Y
  • Disallow root login remotely? [Y/n] Y
  • Remove test database and access to it? [Y/n] Y
  • Reload privilege tables now? [Y/n] Y

Instruct MariaDB to use native password:

mysql -u root mysql -e "update user set plugin='mysql_native_password' where user='root'; flush privileges;"

Set MariaDB root password in a configuration file (the same password configured before!)

cat << EOF > /root/.my.cnf
[client]
user = root
password = MARIADB_ROOT_PASSWORD
EOF

Enable MySQL slow query logging (often useful during slow page load debugging):

sed -i "{s/^#slow_query_log_file /slow_query_log_file /g}" /etc/mysql/mariadb.conf.d/50-server.cnf
sed -i "{s/^#long_query_time /long_query_time /g}" /etc/mysql/mariadb.conf.d/50-server.cnf
sed -i "{s/^#log_slow_rate_limit /log_slow_rate_limit /g}" /etc/mysql/mariadb.conf.d/50-server.cnf
sed -i "{s/^#log_slow_verbosity /log_slow_verbosity /g}" /etc/mysql/mariadb.conf.d/50-server.cnf
sed -i "{s/^#log-queries-not-using-indexes/log-queries-not-using-indexes/g}" /etc/mysql/mariadb.conf.d/50-server.cnf

MySQL is now configured, so restart it:

/etc/init.d/mysql restart

Install phpMyAdmin

The version of phpmyadmin coming with the distribution is not updated so I prefer to install the latest manually:

export VER="5.0.4"
cd /tmp
wget https://files.phpmyadmin.net/phpMyAdmin/${VER}/phpMyAdmin-${VER}-all-languages.tar.gz
tar xvf phpMyAdmin-${VER}-all-languages.tar.gz
rm -f phpMyAdmin-${VER}-all-languages.tar.gz
mv phpMyAdmin* /usr/share/phpmyadmin
mkdir -p /var/lib/phpmyadmin/tmp
chown -R www-data:www-data /var/lib/phpmyadmin
mkdir /etc/phpmyadmin/
cp /usr/share/phpmyadmin/config.sample.inc.php  /usr/share/phpmyadmin/config.inc.php

Now edit the file /usr/share/phpmyadmin/config.inc.php and set secret passphrase and temporary directory:

// https://www.devglan.com/online-tools/bcrypt-hash-generator
$cfg['blowfish_secret'] = 'SECRET_HERE';
[...]
$cfg['TempDir'] = '/var/lib/phpmyadmin/tmp';

Configure Shorewall firewall rules

Copy the default configuration for one interface:

cd /usr/share/doc/shorewall/examples/one-interface
cp interfaces /etc/shorewall/
cp policy /etc/shorewall/
cp rules /etc/shorewall/
cp zones /etc/shorewall/

Now open /etc/shorewall/policy file and change the line:

net             all             DROP            info

removing info directive given it fills the system logs:

net             all             DROP

Now open /etc/shorewall/rules and add the following rules at the bottom of the file:

HTTP/ACCEPT     net             $FW
HTTPS/ACCEPT    net             $FW
SSH/ACCEPT      net             $FW

NOTE: in case you want to allow ICMP (Ping) traffic from a specific remote hosts you need to add a rule similar to the following where xxx.xxx.xxx.xxx is the remote IP address, before the Ping(DROP) rule:

Ping(ACCEPT)    net:xxx.xxx.xxx.xxx       $FW

Now edit /etc/default/shorewall and change startup=0 to startup=1 You are now ready to start the firewall:

/etc/init.d/shorewall start

Setup Postfix

Stop postfix server:

/etc/init.d/postfix stop

Edit /etc/mailname and set your server domain name, for example:

server1.mycompany.com

Restart Postfix:

/etc/init.d/postfix start

Let’s encrypt

In order to get SSL free certificates with let’s encrypt install the powerful (and simple) dehydrated tool:

cd /root
git clone https://github.com/lukas2511/dehydrated.git
cd dehydrated
touch domains.txt
cp docs/examples/config .
/root/dehydrated/dehydrated --register --accept-terms

Prepare Apache2 configuration for letsencrypt:

cat << EOF > /etc/apache2/conf-available/dehydrated.conf
Alias /.well-known/acme-challenge /var/www/dehydrated
<Directory /var/www/dehydrated>
        Options None
        AllowOverride None

        # Apache 2.x
        <IfModule !mod_authz_core.c>
                Order allow,deny
                Allow from all
        </IfModule>

        # Apache 2.4
        <IfModule mod_authz_core.c>
                Require all granted
        </IfModule>
</Directory>
EOF

Enable new config and reload Apache

a2enconf dehydrated
systemctl reload apache2

Log rotation

In order to correctly log files you need to adjust logrotate configuration for Apache:

cat << EOF >> /etc/logrotate.d/apache2
/var/www/vhosts/*/logs/access*.log
{
    rotate 30
    missingok
    size 10M
    compress
    delaycompress
    sharedscripts
    postrotate
        /etc/init.d/apache2 reload > /dev/null
    endscript
}

/var/www/vhosts/*/logs/error*.log
{
    rotate 3
    missingok
    compress
    delaycompress
    size 2M
    sharedscripts
    postrotate
        /etc/init.d/apache2 reload > /dev/null
    endscript
}
EOF

Prepare environment

Create all needed directories and files

mkdir /root/cron_scripts
mkdir -p /var/www/vhosts

Now download all tools to manage the server locally:

wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/ADD_ALIAS.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/ADD_DOMAIN.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/ADD_SSL.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/ALIAS_LIST.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/DEL_ALIAS.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/DEL_DOMAIN.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/DOMAIN_LIST.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/MYSQL_CREATE.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/UPDATE_SFTP_PASSWORD.sh
chmod 770 *.sh

Download also the tools that will be used with cron:

cd /root/cron_scripts
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/cron_scripts/backup_mysql.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian10/LAMP/cron_scripts/mysql_optimize.sh
chmod 770 *.sh
  • Edit /root/ADD_DOMAIN.sh and change ADMIN_EMAIL variable with your email address.

Configure CRON

Edit /etc/crontab and add the following lines at the bottom:

# mysql optimize tables
3  4  *  *  7   root    /root/cron_scripts/mysql_optimize.sh

# mysql backup
32 4  *  *  *   root    /root/cron_scripts/backup_mysql.sh

# letsencrypt
50 2 * * *      root    /root/dehydrated/dehydrated -c > /dev/null

Full web server setup with Debian 9 (Stretch)

Setup bash and update the system

cp /etc/skel/.bashrc /root/.bashrc
apt-get update
apt-get dist-upgrade

Configure hostname correctly

Make sure to have the following two lines (with the same format) at the top of your /etc/hosts file

127.0.0.1       localhost.localdomain localhost
xxx.xxx.xxx.xxx web1.myserver.com web1

Note: xxx.xxx.xxx.xxx is the public IP address assigned to your server.

Install all needed packages

apt-get install vim git acl screen rsync net-tools php mysql-server mysql-client apache2 iptables phpmyadmin varnish shorewall vsftpd php-cli php-curl php-dev php-gd php-imagick php-imap php-memcache php-pspell php-recode php-tidy php-xmlrpc php-pear postfix apg ca-certificates bsd-mailx

MariaDB/PhpMyAdmin:

  • web server to reconfigure automatically: apache2
  • configure database for phpmyadmin with dbconfig-common? Yes
  • MySQL application password for phpmyadmin: [blank]

Postfix:

  • Select Internet Site
  • System mail name: (insert here the FQDN, for example web1.myserver.com)

Setup FTP

Stop VSFTP server:

/etc/init.d/vsftpd stop

Create backup configuration:

mv /etc/vsftpd.conf /etc/vsftpd.conf.backup

Add new configuration:

cat << "EOF" > /etc/vsftpd.conf
listen=YES
listen_port=21
anonymous_enable=NO
local_enable=YES
guest_enable=YES
guest_username=nobody
user_sub_token=$USER
local_root=/var/www/vhosts/$USER
virtual_use_local_privs=YES
user_config_dir=/etc/vsftpd/users
pam_service_name=vsftpd_local_and_virtual
chroot_local_user=YES
chroot_list_enable=YES
chroot_list_file=/etc/vsftpd/chroot_list
ftpd_banner=Welcome to my ftp server
write_enable=YES
download_enable=YES
dirlist_enable=YES
local_umask=022
dirmessage_enable=YES
xferlog_enable=YES
xferlog_file=/var/log/xferlog
connect_from_port_20=YES
connect_timeout=60
data_connection_timeout=300
idle_session_timeout=300
local_max_rate=0
max_clients=0
max_per_ip=3
EOF

Create an empty chroot_list file:

mkdir /etc/vsftpd
touch /etc/vsftpd/chroot_list

Install PAM module for virtual users:

apt-get install libpam-pwdfile

And configure it creating the file /etc/pam.d/vsftpd_local_and_virtual with this content:

# Standard behaviour for ftpd(8).
auth    required        pam_listfile.so item=user sense=deny file=/etc/ftpusers onerr=succeed

# first try to authenticate local users
auth    sufficient      pam_unix.so

# if that failed, login with virtual user
auth    required        pam_pwdfile.so  pwdfile /etc/vsftpd/passwd

# pam_pwdfile doesn't come with account, so we just permit on success
account required        pam_permit.so

Start VSFTP server:

/etc/init.d/vsftpd start

Setup Apache

Stop Apache web server:

/etc/init.d/apache2 stop

Backup Apache configuration:

cp /etc/apache2/apache2.conf /etc/apache2/apache2.conf.backup

Edit the following lines in /etc/apache2/apache2.conf

  • From Timeout 300 to Timeout 45
  • From KeepAliveTimeout 5 to KeepAliveTimeout 15

Edit /etc/apache2/mods-enabled/mpm_prefork.conf:

<IfModule mpm_prefork_module>
        StartServers             5
        MinSpareServers          5
        MaxSpareServers          10
        MaxRequestWorkers        150
        MaxConnectionsPerChild   10000
</IfModule>

Edit /etc/apache2/ports.conf and change the port 80 with 8080 since we are going to use Varnish:

Listen 8080

Change the port (from 80 to 8080) also in the default virtual host /etc/apache2/sites-enabled/000-default.conf

Enable useful Apache modules:

a2enmod ssl
a2enmod rewrite
a2enmod headers
a2enmod deflate
a2enmod proxy
a2enmod proxy_http

Now restart Apache:

/etc/init.d/apache2 restart

Setup Varnish

Stop Varnish daemon:

/etc/init.d/varnish stop

Backup your /etc/varnish/default.vcl and create a new one with this content:

vcl 4.0;
import std;

# Default backend definition. Set this to point to your content server.
backend default {
    .host = "127.0.0.1";
    .port = "8080";
    .connect_timeout = 600s;
    .first_byte_timeout = 600s;
    .between_bytes_timeout = 600s;
}

sub vcl_recv {
    # Happens before we check if we have this in cache already.
    #
    # Typically you clean up the request here, removing cookies you don't need,
    # rewriting the request, etc.

    if (req.url ~ "^/phpmyadmin") {
        return (pass);
    }

    if ((client.ip != "127.0.0.1" && std.port(server.ip) == 80) &&
        (
          (req.http.host ~ "localhost")
          # ENSURE HTTPS - DO NOT REMOVE THIS LINE
        )
    ){
        set req.http.x-redir = "https://" + req.http.host + req.url;
        return (synth(750, ""));
    }
}

sub vcl_synth {
  # Listen to 750 status from vcl_recv.
  if (resp.status == 750) {
    # Redirect to HTTPS with 301 status.
    set resp.status = 301;
    set resp.http.Location = req.http.x-redir;
    return(deliver);
  }
}

sub vcl_backend_response {
    # Happens after we have read the response headers from the backend.
    #
    # Here you clean the response headers, removing silly Set-Cookie headers
    # and other mistakes your backend does.
}

sub vcl_deliver {
    # Happens when we have all the pieces we need, and are about to send the
    # response to the client.
    #
    # You can do accounting or modifying the final object here.
}

Now edit /etc/default/varnish and set the DAEMON_OPTS variable like this:

DAEMON_OPTS="-a :80 \
             -T localhost:6082 \
             -f /etc/varnish/default.vcl \
             -S /etc/varnish/secret \
             -s malloc,256m"

Now we have to make some changes also to systemd scripts (this step is mandatory for Debian Stretch!) since systemd does not consider /etc/default/varnish settings.

Edit /lib/systemd/system/varnish.service and change port 6081 with port 80:

[Unit]
Description=Varnish HTTP accelerator
Documentation=https://www.varnish-cache.org/docs/4.1/ man:varnishd

[Service]
Type=simple
LimitNOFILE=131072
LimitMEMLOCK=82000
ExecStart=/usr/sbin/varnishd -j unix,user=vcache -F -a :80 -T localhost:6082 -f /etc/varnish/default.vcl -S /etc/varnish/secret -s malloc,256m
ProtectSystem=full
ProtectHome=true
PrivateTmp=true
PrivateDevices=true

[Install]
WantedBy=multi-user.target

Restart Varnish:

systemctl daemon-reload
systemctl restart varnish.service

Setup MariaDB

Secure MariaDB installation:

mysql_secure_installation
  • Enter current password for root (enter for none): [ENTER]
  • Set root password? [Y/n] Y
  • Write your MARIAB_ROOT_PASSWORD
  • Remove anonymous users? [Y/n] Y
  • Disallow root login remotely? [Y/n] Y
  • Remove test database and access to it? [Y/n] Y
  • Reload privilege tables now? [Y/n] Y

Instruct MariaDB to use native password:

mysql -u root mysql -e "update user set plugin='mysql_native_password' where user='root'; flush privileges;"

Set MariaDB root password in a configuration file (the same password configured before!)

cat << EOF > /root/.my.cnf
[client]
user = root
password = MARIADB_ROOT_PASSWORD
EOF

Enable MySQL slow query logging (often useful during slow page load debugging):

sed -i "{s/^#slow_query_log_file /slow_query_log_file /g}" /etc/mysql/mariadb.conf.d/50-server.cnf
sed -i "{s/^#long_query_time /long_query_time /g}" /etc/mysql/mariadb.conf.d/50-server.cnf
sed -i "{s/^#log_slow_rate_limit /log_slow_rate_limit /g}" /etc/mysql/mariadb.conf.d/50-server.cnf
sed -i "{s/^#log_slow_verbosity /log_slow_verbosity /g}" /etc/mysql/mariadb.conf.d/50-server.cnf
sed -i "{s/^#log-queries-not-using-indexes/log-queries-not-using-indexes/g}" /etc/mysql/mariadb.conf.d/50-server.cnf

MySQL is now configured, so restart it:

/etc/init.d/mysql restart

Fix for PhpMyAdmin redirecting to port 8080

If you try to access to http://yoursitename/phpmyadmin you are redirected to http://yoursitename:8080/phpmyadmin that will not work unless you open the firewall rule for port 8080 as described below. This because the web server is actually running on port 8080. To workaround this and have the PhpMyAdmin working on port 80 you need to force the redirect:

cat << "EOF" > /etc/phpmyadmin/conf.d/fix-redirection.php
<?php
$cfg['PmaAbsoluteUri'] = $_SERVER['REQUEST_SCHEME'].'://'.$_SERVER['SERVER_NAME'].'/phpmyadmin';
EOF

Configure Shorewall firewall rules

Copy the default configuration for one interface:

cd /usr/share/doc/shorewall/examples/one-interface
cp interfaces /etc/shorewall/
cp policy /etc/shorewall/
cp rules /etc/shorewall/
cp zones /etc/shorewall/

cd /usr/share/doc/shorewall6/examples/one-interface
cp interfaces /etc/shorewall6/
cp policy /etc/shorewall6/
cp rules /etc/shorewall6/
cp zones /etc/shorewall6/

Now open /etc/shorewall/policy file and change the line:

net             all             DROP            info

removing info directive given it fills the system logs:

net             all             DROP

Now open /etc/shorewall/rules and add the following rules at the bottom of the file:

HTTP/ACCEPT     net             $FW
HTTPS/ACCEPT     net             $FW
SSH/ACCEPT      net             $FW
FTP/ACCEPT      net             $FW

# real apache since varnish listens on port 80
#ACCEPT         net             $FW             tcp             8080

NOTE: in case you want to allow ICMP (Ping) traffic from a specific remote hosts you need to add a rule similar to the following where xxx.xxx.xxx.xxx is the remote IP address, before the Ping(DROP) rule:

Ping(ACCEPT)    net:xxx.xxx.xxx.xxx       $FW

Now edit /etc/default/shorewall and change startup=0 to startup=1 You are now ready to start the firewall:

/etc/init.d/shorewall start

Setup Postfix

Stop postfix server:

/etc/init.d/postfix stop

Edit /etc/mailname and set your server domain name, for example:

server1.mycompany.com

Then, in order to monitor mail traffic coming from PHP you need to edit /etc/php/7.0/apache2/php.ini. Go to [mail function] section and set the following two options:

sendmail_path = /usr/local/bin/sendmail-wrapper
auto_prepend_file = /usr/local/bin/env.php

Now create the two files above in /usr/local/bin:

sendmail-wrapper:

#!/bin/sh
logger -p mail.info sendmail-wrapper.sh: site=${HTTP_HOST}, client=${REMOTE_ADDR}, script=${SCRIPT_NAME}, pwd=${PWD}, uid=${UID}, user=$(whoami)
/usr/sbin/sendmail -t -i $*

env.php:

<?php
putenv("HTTP_HOST=".@$_SERVER["HTTP_HOST"]);
putenv("SCRIPT_NAME=".@$_SERVER["SCRIPT_NAME"]);
putenv("SCRIPT_FILENAME=".@$_SERVER["SCRIPT_FILENAME"]);
putenv("DOCUMENT_ROOT=".@$_SERVER["DOCUMENT_ROOT"]);
putenv("REMOTE_ADDR=".@$_SERVER["REMOTE_ADDR"]);
?>

Now make they both have executable flag:

chmod +x /usr/local/bin/sendmail-wrapper
chmod +x /usr/local/bin/env.php

Add also /usr/local/bin/ to the open_basedir php list in /etc/apache2/conf-enabled/phpmyadmin.conf

php_admin_value open_basedir /usr/share/phpmyadmin/:/etc/phpmyadmin/:/var/lib/phpmyadmin/:/usr/local/bin/

Restart Postfix:

/etc/init.d/postfix start

Let’s encrypt

In order to SSL free certificates with let’s encrypt install the powerful (and simple) dehydrated tool:

cd /root
git clone https://github.com/lukas2511/dehydrated.git
cd dehydrated
touch domains.txt
cp docs/examples/config .

Prepare Apache2 configuration for letsencrypt:

cat << EOF > /etc/apache2/conf-available/dehydrated.conf
Alias /.well-known/acme-challenge /var/www/dehydrated
<Directory /var/www/dehydrated>
        Options None
        AllowOverride None

        # Apache 2.x
        <IfModule !mod_authz_core.c>
                Order allow,deny
                Allow from all
        </IfModule>

        # Apache 2.4
        <IfModule mod_authz_core.c>
                Require all granted
        </IfModule>
</Directory>
EOF

Enable new config and reload Apache

a2enconf dehydrated
systemctl reload apache2

Log rotation

In order to correctly log files you need to adjust lograte configuration for Apache:

cat << EOF >> /etc/logrotate.d/apache2
/var/www/vhosts/*/logs/access*.log
{
    rotate 30
    missingok
    size 10M
    compress
    delaycompress
    sharedscripts
    postrotate
        /etc/init.d/apache2 reload > /dev/null
    endscript
}

/var/www/vhosts/*/logs/error*.log
{
    rotate 3
    missingok
    compress
    delaycompress
    size 2M
    sharedscripts
    postrotate
        /etc/init.d/apache2 reload > /dev/null
    endscript
}
EOF

Prepare environment

Create all needed directories and files

mkdir /root/cron_scripts
mkdir -p /var/www/vhosts
mkdir -p /etc/vsftpd/users
touch /etc/vsftpd/passwd

Now download all tools to manage the server locally:

wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/ADD_ALIAS.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/ADD_DOMAIN.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/ADD_FTP_VIRTUAL_USER.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/ADD_SSL.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/ALIAS_LIST.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/CLEAN_VARNISH_CACHE.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/DEL_ALIAS.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/DEL_DOMAIN.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/DEL_FTP_VIRTUAL_USER.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/DOMAIN_LIST.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/MYSQL_CREATE.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/UPDATE_ALL_FTP_PASSWORD.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/UPDATE_FTP_PASSWORD.sh
chmod 770 *.sh

Download also the tools that will be used with cron:

cd /root/cron_scripts
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/cron_scripts/backup_mysql.sh
wget https://raw.githubusercontent.com/matteomattei/servermaintenance/master/Debian9/LAMP/cron_scripts/mysql_optimize.sh
chmod 770 *.sh
  • Edit /root/ADD_DOMAIN.sh and change ADMIN_EMAIL variable with your email address.

Configure CRON

Edit /etc/crontab and add the following lines at the bottom:

# mysql optimize tables
3  4  *  *  7   root    /root/cron_scripts/mysql_optimize.sh

# mysql backup
32 4  *  *  *   root    /root/cron_scripts/backup_mysql.sh

# letsencrypt
50 2 * * *      root    /root/dehydrated/dehydrated -c > /dev/null