On Wed, Jan 14, 2009 at 12:41 AM, Greg Beeley <greg.bee...@lightsys.org> wrote: > Steve I agree with you on this one. Both input validation and output encoding > are countermeasures to the same basic problem...
I'd like to offer a different view for your consideration, which is that input validation and output encoding actually don't have anything to do with security. Those techniques are essential software building blocks. While it is true that omission to use these techniques often causes security issues, that only means such programs are insecure in addition to being defective. I think that it's inherently wrong to associate input validation and output encoding with security. Fix the defects and the security issues will go away. On the other hand, if you only fix the security issues you may be left with a number of defects on your hands. Input validation layers should focus on accepting only valid data (per business requirements), while code that transmits data across system boundaries should focus on using the exchange and communication protocols correctly. Actually, now that I think about it more, I think we are struggling with the term input validation because the term has been overloaded. In the one sense, we are talking about validating user input, which mostly needs to concern itself with adhering to business requirements. This meaning is not very important for security, but the other one, validating data before something is done with it, is. If you take a web application for example, you would ideally verify that all user submitted data adheres to your business requirements. -- Ivan Ristic _______________________________________________ Secure Coding mailing list (SC-L) SC-L@securecoding.org List information, subscriptions, etc - http://krvw.com/mailman/listinfo/sc-l List charter available at - http://www.securecoding.org/list/charter.php SC-L is hosted and moderated by KRvW Associates, LLC (http://www.KRvW.com) as a free, non-commercial service to the software security community. _______________________________________________
