By Stephen Mencik SearchSecurity site expert Stephen Mencik offers his advice for securing a Web server in this Ask the Expert Q&A. Q: How can we protect our Web server from external attack? There are a number of things you can do to protect yourself against external attacks. First, the Web server should have only those services running that are absolutely needed. Second, the operating system and applications should all have the most recent security patches installed. The OS should be "hardened" as much as possible. A paper that is OpenBSD centric, but has some application to hardening all operating systems, can be found at
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http://geodsoft.com/howto/harden/hardintro.htm.
Third, it should sit behind a firewall that only allows those ports
needed for operation. For example, if it is purely a Web server that
does not need any access from the outside other than via http and
https, then only ports 80 and 443 need to be open. However, if you
are running a Web hosting company, your clients need to be able to
upload files and more. So you'll probably need to enable the ports
for FTP and Telnet. If you are combining this with e-mail services,
you'll need to open the ports for POP and SMTP, or whatever protocols
you use for mail. (For more information on ports, go to
http://searchsecurity.techtarget.com/ateQuestionNResponse/0,289625,sid14_cid407639_tax285453,00.html.)
Fourth, all form input should be validated by the script that handles
the form. Buffer overflows are a favorite type of attack. A good
reference for CGI script security is located at
http://www.w3.org/Security/Faq/wwwsf4.html.
Fifth, make use of audit logs. Use TCP Wrappers where you can.
Sixth, make regular backups. Even the best security planning is not
perfect. Someone still might find a way to break in. And even if
there is no security break-in, you might lose a hard drive. So, you
still want to have regular backups.
Essentially, you want to do everything you can think of to improve
the security of the machine. You can do some Web searches for
security information on your particular combination of OS and Web
server application and find lots of good advice on the best things to
do to make the server as secure as possible.
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Related Book Administrating Web servers, security and maintenance
By Eric Larson & Brian Stephens
Publisher Name: Prentice Hall
Date published: Dec. 1999
Pages: 350
Cover Type: Soft Cover
Summary:
This book is designed to provide individuals with the core skills needed to meet the demands of the Web development and Internet community. This user-friendly interactive text provides competency in three key skill areas: 1. Web Business Management, from financial issues to project management and marketing. 2. Content Management, including user interface, authoring languages, multimedia and graphics. 3. Technical Management involving administration, protocols, performance and security.
This was first published in September 2001