HTTP attacks: Strategies for prevention

There are two common HTTP attacks. One involves sending a long URL to a Web server with the goal of triggering a buffer overflow. The other attack is the SQL injection, which is the process of sending appended SQL commands to a URL to gain access to the backend database. Attackers often use forms to perform these attacks, as they both look to exploit poorly-written applications using unexpected, user-submitted data to initiate the attack. This means all user input data needs to be checked before being sent to another process. For example, if input data is used to build a Web page or is retrieved from a database, it must be checked before being published to ensure that any erroneous data is removed and the code runs correctly.

To prevent these types of attack, your organization's application security strategy should include the following:

• Continual testing for technical and logical vulnerabilities during the development cycle. Two approaches to this are dynamic analysis and static analysis. Dynamic analysis involves actually running the software. Static analysis involves analyzing the software without executing it, which offers the benefit of performing the test earlier in the development cycle.

• Develop procedures for completing component-level integration testing, system integration testing, and application function and deployment testing. While this may seem onerous, Gartner estimates that the cost of removing a vulnerability during testing is less than 2% of the cost of removing it from a production system.

• Make sure you include change management, because the change rate in Web application code is normally high, which rapidly reduces the relevance of existing security reviews. In order to evaluate the impacts of any changes on overall system application security, the security assessment process should always be repeated when the business logic in the application changes.

• Ensure proper training of developers. While training developers to write secure code doesn't necessarily mean the code they write will be secure, the more they understand how Web servers and browsers interact, and the protocols used in Internet communications, the more likely they are to build applications that aren't vulnerable to these attacks. Microsoft, in partnership with SPI Dynamics, is running an application development security awareness campaign and is providing free webcasts and workshops.

Here are 11 rules that developers should follow during any Web application development cycle:

More Information Visit our Web Security School to learn how to harden a Web server and how to prevent hackers from breaking into a network. Read this tip to learn ten dos and don'ts for secure coding. Visit our resource center for news, tips and expert advice on how to combat SQL injection, buffer overflows and other application attacks.

1. Never trust user supplied data
2. Clean and validate all user input
3. Validate data on the server
4. Use taint checking or .NET validation controls
5. Use POST instead of GET
6. Avoid the use of HIDDEN form fields
7. Only use cookies to store a session ID
8. Locate different file types in separate directories
9. Use absolute path and filenames
10. Open files as read-only where possible
11. Keep up to date on the latest attack methods

About the author:
Michael Cobb, CISSP-ISSAP is the founder and managing director of Cobweb Applications Ltd., a consultancy that offers IT training and support in data security and analysis. He co-authored the book IIS Security and has written numerous technical articles for leading IT publications. Mike is the guest instructor for SearchSecurity's Web Security School and, as a SearchSecurity.com site expert, answers user questions on application and platform security.

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 Web Security Advisor,   Application and Platform Security,   Web Security Tools and Best Practices,   Web Application Security,   Application Attacks (Buffer Overflows, Cross-Site Scripting),   VIEW ALL TAGS Digg This!     StumbleUpon     Del.icio.us    RELATED CONTENT Web Security Advisor DNS rebinding defenses still necessary, thanks to Web 2.0 New defenses for automated SQL injection attacks PCI compliance and Web applications: Code review or firewalls? Worst practices: Bad security incidents to avoid Web scanning and reporting best practices Social networking Web site threats manageable with good enterprise policy Enterprise security in 2008: Building trust into the application development process PCI DSS Section 6: A plan for tackling application security Making the case for Web application vulnerability scanners Preparing for uniform resource identifier (URI) exploits Web Application Security Cisco acquires SaaS security vendor ScanSafe Web application firewall use goes beyond compliance, company finds Gumblar Trojan drive-by exploits spike following Adobe update Some Facebook applications lead to Russian attack sites Barracuda acquires Purewire expanding Web security reach An enterprise strategy for Web application security threats Scanning with N-Stalker offers basic Web application security assessment Attackers target PDF, DirectShow flaws with malicious banner ads New Bahama botnet evades search engines, fuels click fraud Experts rebuke programmers who use SQL injection as feature Application Attacks (Buffer Overflows, Cross-Site Scripting) Adobe warns of critical update for Reader, Acrobat 9.1.3 9 Ways to Improve Application Security After an Incident Developers Need Help with Security Errors Buffer overflow tutorial: How to find vulnerabilities, prevent attacks SQL injection protection: A guide on how to prevent and stop attacks Experts rebuke programmers who use SQL injection as feature SANS: Application threats, website flaws pose biggest security threats Mozilla helps Adobe push out faster patches SSH key compromise shuts down Apache website IBM finds sharp spike in malicious content on trusted sites Application Attacks (Buffer Overflows, Cross-Site Scripting) Research RELATED GLOSSARY TERMS Terms from Whatis.com − the technology online dictionary anonymous Web surfing  (SearchSecurity.com) buffer overflow  (SearchSecurity.com) cache cramming  (SearchSecurity.com) cookie poisoning  (SearchSecurity.com) dictionary attack  (SearchSecurity.com) distributed denial-of-service attack  (SearchSecurity.com) JavaScript hijacking  (SearchSecurity.com) National Computer Security Center  (SearchSecurity.com) threat modeling  (SearchSecurity.com) trigraph  (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.