Tag: linux

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How to change hostname in Ubuntu server

Here’s how you can change hostname in Ubuntu server

1. Edit /etc/hostname, and change the hostname
2. Edit /etc/hosts file, and add the hostname to 127.0.0.1, or to any local machine ip
3. run, “sudo server hostname stop”, and “sudo server hostname start”

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Please update/patch and secure Litespeed web server

Due to the widespread of Litespeed 0-day attack which has affected local websites, it’s imperative for all sysadmin and website operator to patch/update and upgrade the security of the Litespeed web server.

This attack is dangerous particularly because the attacker can gain shell access with the same privileges of the web server or the user that runs the web server. Usually this allow the attacker to peek into database content and downloads it.

Patch now!, the security and privacy of your users are at the stake!

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How to Hide Apache2 and PHP version without using mod_security in Ubuntu Linux

Although security by obscurity is not the best policy to protect your IS assets, but it is still useful to thwarts simple network scanner or newbie crackers.

Note: This tip is written for Ubuntu Linux, the steps is similar to other GNU/Linux distro, albeit with a slight variant.

Hiding Apache2 version
Edit /etc/apache2/apache2.conf

Add these lines at the end of the file:
ServerSignature Off
ServerTokens Prod

Restart Apache2
[bash]
sudo /etc/init.d/apache2 restart
[/bash]

Hiding PHP version
Edit /etc/php5/apache2/php.ini file

Find these lines, and switch it off:
expose_php = Off
display_errors = Off

Additionally you may disable certain ‘risky’ functions in php by editing the disable_functions line:
disable_functions = phpinfo, system,show_source,

Finally, you may restart Apache2 web server.
[bash]
sudo /etc/init.d/apache2 restart
[/bash]

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Limiting the number of connections to SSH Server using Iptables

This is the quickest way to limit the number of connection to your SSH server with iptables.

[bash]
sudo /sbin/iptables -A INPUT -p tcp –syn –dport 22 -m connlimit –connlimit-above 5 -j REJECT
[/bash]

This will only allow up to 5 concurrent connections to the SSH server, subsequent connections will be rejected by iptables, thus this can thwarts Brute-force attempts to your server.

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