Ubuntu Tutorials » Security

Install mod_spamhaus Apache module to fight comment spam

aip — Tue, 01 Jun 2010 20:58:02 +0000

mod_spamhaus is an Apache module for DNS Block Listing that protects web services by denying access to particular IP addresses. It can stop spam relaying via web form URL injection, and block HTTP DDoS attacks from bot-nets.

It queries sbl-xbl.spamhaus.org, taking advantage of the Spamhaus Block List (SBL) and the Exploits Block List (XBL).

1. Install the package

apt-get install libapache2-mod-spamhaus

Apache is automatically restarted and the module is enabled. If you would like to test the module you can add a line to your hosts file to make it think that your IP address is blocked (pico /etc/hosts)

127.0.0.4 1.0.168.192.sbl-xbl.spamhaus.org

Replace 1.0.168.192 with your IP address and reverse it. The IP address 192.168.0.1 should read 1.0.168.192.

By default, only POST, PUT, OPTIONS, CONNECT methods are blocked. You can add GET to the list of methods blocked in /etc/apache2/mods-enabled/mod-spamhaus.conf to block the spammers from seeing your website.

Disable root login to SSH

aip — Mon, 09 Nov 2009 20:16:46 +0000

Allowing root logins to your SSH damon is a big security threat. If the SSH port is open, hackers will probably at some time attempt to brute force your root password. It's a good idea to disable root logins to SSH and instead use a normal user to login and use sudo to perform tasks that require root privileges.

1. Open the SSH daemon config file and change this line: (sudo pico /etc/ssh/sshd_config)

PermitRootLogin no

2. Restart the SSH daemon

sudo /etc/init.d/ssh restart

Add a sudoer (user allowed to use sudo)

aip — Thu, 05 Nov 2009 17:32:41 +0000

Sudo allows a system administrator to delegate authority to give certain users (or groups of users) the ability to run some (or all) commands as root or another user while providing an audit trail of the commands and their arguments.

1. Create a new user (optional)

adduser user1

2. As root, run this command:

visudo

3. Add this line into the file:

user1 ALL=(ALL) ALL

This will allow user1 to run all commands as root. You can also limit the access, Click here to view the syntax

4. Save the file by pressing Ctrl-X if you are using Nano or :w if using vi