How to Cheat at Application Security

Developers need to know a lot in order to build secure applications. Some of this is good software engineering and defensive design and programming – using (safe) APIs properly, carefully checking for errors and exceptions, adding diagnostics and logging, and never trusting anything from outside of your code (including data and other people’s code). But there are also lots of technical details about security weaknesses and vulnerabilities in different architectures and platforms and technology-specific risks that you have to understand and that you have to make sure that you deal with properly. Even appsec specialists have trouble keeping up with all of it.

This is where OWASP’s Cheat Sheets come in. They provide a clear explanation of security problems, and tools and patterns and practical steps that you can follow to prevent them or solve them.

There are more than 30 cheat sheets available today, on everything from how to handle authentication in web apps to using HTML5 safely to what IOS developers should look out for when developing secure mobile apps.

Some of the cheat sheets are easy for developers to understand and use right away. For example, the cheat sheets on common security problems like SQL injection and CSRF explain what these vulnerabilities are, and what works and what doesn’t to protect from them. Simple and practical advice from people who know.

There are also cheat sheets on basic development problems and requirements that you might think that you already understand – things that seem straightforward, but that need to be done carefully and correctly to make sure that your system is secure. Cheat sheets on how to do logging securely and the right way to use parameterized queries (prepared statements) and how to properly implement a Forgot Password feature, and on Session Management. Make sure that you read the cheat sheet on Input Validation - there’s a lot more to doing it right than you think.

Then there are cheat sheets on harder, uglier technical problems like secure cryptographic storage or what you have to do to avoid XSS. XSS is so ugly that there is also a second cheat sheet that tries to explain the problem and solutions in a simpler way; and another cheat sheet just on DOM-based XSS prevention; and a technical cheat sheet on XSS filter evasion to help test for XSS vulnerabilities.

The OWASP Cheat Sheets are shortcuts that take you straight to the explanation of specific problems and how to solve them, checklists that you can follow without demanding that you understand everything about appsec. It’s OK. Go ahead and cheat.