Security Best Practices

The security of our servers is of paramount importance. We have a strict security policy that encompasses many areas including a security-hardened operating system, functional isolation of each VDS, and careful monitoring and updating of applications. However, our customers must also share in the responsibility of keeping each of their VDS accounts secure by using good passwords, avoiding insecure scripts and applications, and following other security best practices.

Some of you may have seen reports of distributed server scans that are initiated by potential hackers. Essentially, these hackers scan Internet servers for vulnerable scripts and/or vulnerable users (users with weak passwords). One of the most popular of these scans is trying to log in to SSH as common users like 'root', 'guest', 'admin', or 'test' and then attempting to crack weak passwords (it's even easier if no password has been configured for one of these users). We think it is important to make you aware of these scans and also provide you information that will keep you from becoming a victim of one of these attacks.

One of the benefits of our VDS plans is root access. Every VDS account is provisioned with a root user. Because the root user has significant flexibility and power, it is important that this feature be used carefully.

First, you should set a strong password for all users, especially the root user. Choose a password that uses a variety of characters on the keyboard. Specifically, choose a password that meets the following criteria:

• Your password has both upper and lower case letters.
• Your password has digits, punctuation marks, or other symbols (do not use a word where some letters are simply replaced by digits such as bl0wf1sh).
• Your password is not based on your username.
• Your password is not a real word (e.g., something you'd find in a dictionary or a list of proper nouns).
• Your password is seven or eight characters long.
• Your password is something you can memorize; if you can't seem to memorize something with strange characters, make your password longer, preferably 12 characters or more; adding just one or two characters to your password length has a huge effect mathematically on the strength of your password.
• Change your password at least every six months and change it immediately if you've had to log in over plain text for any reason.
  For additional information on choosing a strong password, please see Choosing a password.

Second, you should always log in to your VDS server as a user OTHER THAN 'root' (either as the admin user created during account provisioning or some other user you've added) and then 'su' to root when you need to do something as root. Additionally, never run a website as root (where the website files are owned by the root user).

Lastly, it is important to secure access to applications that are frequently the subject of scans (like SSH). Here are a few important tips for securing SSH:

• Set "PermitRootLogin no" in sshd_config: now *any* root log in attempts will fail. You should log in to a user account (with a good password!) and then 'su' to root as needed.
  sshd_config is located in the /etc/ssh/ directory.
• There are other settings in sshd_config that can be modified; refer to the ssh_config man page.
  Specifically review MaxStartups, which specifies the maximum number of concurrent unauthenticated connections to the ssh daemon, and PasswordAuthentication, which can be set to 'no', thus requiring SSH users to log in with a private key instead of a password. sshd_config is located in the /etc/ssh/ directory.

For details on the above recommendations and other tips for securing your VDS servers, please see the following pages:

• Methods for Securing Root Access
• Controlling Services on the VDS