Building application firewall rule bases

A recent Gartner Inc. study highlighted this risk by estimating that 75% of today's successful attacks occur at the application layer. It made an even more frightening prediction: by the year 2009, 80% of enterprises will fall victim to an application-layer attack.

Why are these attacks so successful? The answer is quite simple: they bypass all of the network-centric controls that security personnel have implemented over the last ten years, such as port blocking. Consider Web application attacks, for example. Traditional firewalls protecting a Web server contain rules that block all sorts of unwanted traffic, only allowing TCP traffic to traverse the firewall via ports 80 or 443. Unfortunately, the firewall can't distinguish desirable port 80 traffic from undesirable port 80 traffic.

This is where application firewalls come into play. These firewalls perform application-layer inspection of HTTP traffic before it reaches the Web server. The devices are able to inspect a connection and analyze the nature and type of commands that users are providing to the application. They can then analyze the traffic for signatures of known attacks or deviations from profiles of standard

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While application firewalls have great potential, the process of deploying them should be slow and deliberate. Back when network firewalls first entered the enterprise, implementation managers typically adopted a cautious approach to these projects, conducting careful analysis and extensive testing. That same approach should be applied when deploying a Web application firewall. Careful testing builds confidence among an organization's application developers, serving as leverage security managers can use to convince them that the technology will help the enterprise more than it will hinder their day-to-day lives.

Once an organization is ready to move the product into the production environment, it's time to think about a solid firewall rule base. Here's a step-by-step approach for building and deploying application firewall rule bases in an organization: Like network firewalls, application firewalls are not a panacea. Tools like WebInspect and AppScan can be used to test Web applications for vulnerabilities. Complementing these efforts with periodic penetration testing is a solid defensive strategy and can put many security professionals' Web application fears to rest.

About the author: Mike Chapple, CISA, CISSP, is an IT security professional with the University of Notre Dame. He previously served as an information security researcher with the National Security Agency and the U.S. Air Force. Mike is a frequent contributor to SearchSecurity, a technical editor for Information Security magazine and the author of several information security titles, including the CISSP Prep Guide and Information Security Illuminated.

Rate this Tip To rate tips, you must be a member of SearchSecurity.com. Register now to start rating these tips. Log in if you are already a member. BROWSE BY TAG Network Security Tactics,   Network Security: Tools, Products, Software,   Network Firewalls, Routers and Switches,   Enterprise Network Security,   Application and Platform Security,   Application Firewall Security,   VIEW ALL TAGS Digg This!     StumbleUpon     Del.icio.us    RELATED CONTENT Network Security Tactics Screencast: Samurai offers pen-testing nirvana Firewall rule management best practices Chained Exploits: How to prevent phishing attacks from corporate spies Rootkit Hunter demo: Detect and remove Linux rootkits Enterprise UTM security: The best threat management solution? Making the case for network security configuration management An inside look at security log management forensics investigations How to find sensitive information on the endpoint How to perform Microsoft Baseline Security Analyzer (MBSA) scans How to spot attacks through Apache Web server log analysis Network Firewalls, Routers and Switches Firewall rule management best practices Should enterprises be running multiple firewalls? What are the disadvantages of proxy-based firewalls? IT pros find corporate firewall rules tough to navigate PCI compliance requirement 1: Firewalls Comparing an application proxy firewall and a gateway server firewall Microsoft Threat Management Gateway has some drawbacks Rising Profile Front-end/back-end firewalls vs. chassis-based firewalls How to configure a firewall to communicate with an upstream router Application Firewall Security Common PCI questions: Web application firewalls or source code review? Citrix virtual desktop, app delivery controller includes security benefits How to choose between source code reviews or Web application firewalls Check Point adds virtual firewall appliance Web application firewall deployments gain traction Positive changes coming to ModSecurity Best practices for application-level firewall selection and deployment PCI Council issues clarification on Web application security Will firewalls have to adapt to applications that use port 80? NAC, disk encryption gaining attention, survey shows RELATED GLOSSARY TERMS Terms from Whatis.com − the technology online dictionary bastion host  (SearchSecurity.com) firewall  (SearchSecurity.com) Firewall Builder  (SearchSecurity.com) screened subnet  (SearchSecurity.com) virus  (SearchSecurity.com) RELATED RESOURCES 2020software.com, trial software downloads for accounting software, ERP software, CRM software and business software systems Search Bitpipe.com for the latest white papers and business webcasts Whatis.com, the online computer dictionary DISCLAIMER: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.