Running a WHM like Cpanel can sure make hosting easy, but unfortunately running a WHM often makes your server much less secure than it was before!
We do not guaranty that the following steps will make your server hack proof, but it will greatly reduce your chances of compromise. Also note that Layered Technologies does not manage your server and if you do not feel comfortable making system level changes to your server we recommend you open a level2 support ticket (for a fee) or hire a third party sysadmin service to help you.
Basic Steps to Securing CPanel (Linux based OS):
These are items inside of WHM/Cpanel that should be changed to secure your server.
Goto Server Setup =>> Tweak Settings
Check the following items…
Under Domains
Prevent users from parking/adding on common internet domains. (ie hotmail.com, aol.com)
Under Mail
Attempt to prevent pop3 connection floods
Default catch-all/default address behavior for new accounts – blackhole
Under System
Use jailshell as the default shell for all new accounts and modified accounts
Goto Server Setup =>> Tweak Security
Enable php open_basedir Protection
Enable mod_userdir Protection
Disabled Compilers for unprivileged users.
Goto Server Setup =>> Manage Wheel Group Users
Remove all users except for root and your main account from the wheel group.
Goto Server Setup =>> Shell Fork Bomb Protection
Enable Shell Fork Bomb/Memory Protection
When setting up Feature Limits for resellers in Resellers =>> Reseller Center, under Privileges always disable Allow Creation of Packages with Shell Access and enable Never allow creation of accounts with shell access; under Root Access disable All Features.
Goto Service Configuration =>> FTP Configuration
Disable Anonymous FTP
Goto Account Functions =>> Manage Shell Access
Disable Shell Access for all users (except yourself)
Goto Mysql =>> MySQL Root Password
Change root password for MySQL
Goto Security and run Quick Security Scan and Scan for Trojan Horses often. The following and similar items are not Trojans:
/sbin/depmod
/sbin/insmod
/sbin/insmod.static
/sbin/modinfo
/sbin/modprobe
/sbin/rmmod
These are measures that can be taken to secure your server, with SSH access.
Udate OS, Apache and CPanel to the latest stable versions.
This can be done from WHM/CPanel.
Restrict SSH Access
To restrict and secure SSH access, bind sshd to a single IP that is different than the main IP to the server, and on a different port than port 22.
SSH into server and login as root.
Note: You can download Putty by Clicking Here. It’s a clean running application that will not require installation on Windows-boxes.
At command prompt type: pico /etc/ssh/sshd_config
Scroll down to the section of the file that looks like this:
Code:
#Port 22
#Protocol 2, 1
#ListenAddress 0.0.0.0
#ListenAddress ::
Uncomment and change
#Port 22
to look like
Port 5678 (choose your own 4 to 5 digit port number (49151 is the highest port number)
Uncomment and change
#Protocol 2, 1
to look like
Protocol 2
Uncomment and change
#ListenAddress 0.0.0.0
to look like
ListenAddress 123.123.123.15 (use one of your own IP Addresses that has been assigned to your server)
Note 1: If you would like to disable direct Root Login, scroll down until you find
#PermitRootLogin yes
and uncomment it and make it look like
PermitRootLogin no
Save by pressing Ctrl o on your keyboard, and then exit by pressing Ctrl x on your keyboard.
Now restart SSH
At command prompt type: /etc/rc.d/init.d/sshd restart
Exit out of SSH, and then re-login to SSH using the new IP or nameserver, and the new port.
Disable Telnet
To disable telnet, SSH into server and login as root.
At command prompt type: pico -w /etc/xinetd.d/telnet
change disable = no to disable = yes
Save and Exit
At command prompt type: /etc/init.d/xinetd restart
Server e-mail everytime someone logs in as root
To have the server e-mail you everytime someone logs in as root, SSH into server and login as root.
At command prompt type: pico .bash_profile
Scroll down to the end of the file and add the following line:
echo ‘ALERT – Root Shell Access on:’ `date` `who` | mail -s “Alert: Root Access from `who | awk ‘{print $6}’`” [email protected]
Save and exit.
Set an SSH Legal Message
To an SSH legal message, SSH into server and login as root.
At command prompt type: pico /etc/motd
Enter your message, save and exit.
Note: I use the following message…
Code:
ALERT! You are entering a secured area! Your IP and login information
have been recorded. System administration has been notified.
This system is restricted to authorized access only. All activities on
this system are recorded and logged. Unauthorized access will be fully
investigated and reported to the appropriate law enforcement agencies.
Now everytime someone logs in, they will see this message… go ahead a try it.
Disable Shell Accounts
To disable any shell accounts hosted on your server SSH into server and login as root.
At command prompt type: locate shell.php
Also check for:
locate irc
locate eggdrop
locate bnc
locate BNC
locate ptlink
locate BitchX
locate guardservices
locate psyBNC
locate .rhosts
Note: There will be several listings that will be OS/CPanel related. Examples are
/home/cpapachebuild/buildapache/php-4.3.1/ext/ircg
/usr/local/cpanel/etc/sym/eggdrop.sym
/usr/local/cpanel/etc/sym/bnc.sym
/usr/local/cpanel/etc/sym/psyBNC.sym
/usr/local/cpanel/etc/sym/ptlink.sym
/usr/lib/libncurses.so
/usr/lib/libncurses.a
etc.
Disable identification output for Apache
To disable the version output for proftp, SSH into server and login as root.
At command prompt type: pico /etc/httpd/conf/httpd.conf
Scroll (way) down and change the following line to
ServerSignature Off
Restart Apache
At command prompt type: /etc/rc.d/init.d/httpd restart
These are applications that will help to secure your server.
Install chkrootkit
To install chrootkit, SSH into server and login as root.
At command prompt type: cd /root/
At command prompt type: wget ftp://ftp.pangeia.com.br/pub/seg/pac/chkrootkit.tar.gz
At command prompt type: tar xvzf chkrootkit.tar.gz
At command prompt type: cd chkrootkit-0.44
At command prompt type: make sense
To run chkrootkit
At command prompt type: /root/chkrootkit-0.44/chkrootkit
Make sure you run it on a regular basis, perhaps including it in a cron job.