Secure Web Application Development and Implementation

The UK's Centre for the Protection of National Infrastructure (CPNI) has updated its guidance on protecting business applications with the publication this month of a new document on developing and implementing secure web applications.

Development and Implementation of Secure Web Applications is a well-written and digestible 81-page A4 document arranged in seven main sections:

• Introduction to web application security
• General aspects of web application security
• Access handling (authentication, session management and access control)
• Injection flaws
• Application users and security
• Thick client security
• Preparing the infrastructure

It appears to replace the good, but somewhat dated document "Briefing 10/2006 - Secure web Applications - Development, Installation and Security Testing" created by their predecessor National Infrastructure Security Co-ordination Centre (NISCC), and issued in April 2006. The new document is more compact and focused, and I think I prefer it. Yes of course it is more up-to-date, and while it would be possible to argue why some things are included and not others, these others things tend to be explained further in the references. It's clear there is considerable overlap with information from OWASP and the Microsoft SDL, but I'm sure the reverse is true to an extent too.

It is very encouraging CPNI have taken the time to produce an updated document, but that probably reflects the types of risks facing their audience. I am especially pleased to see the section on infrastructure, since application security cannot be an island on its own. I would say the guidance is probably on the medium-to-heavy weight side of advice, but that is probably appropriate for critical national infrastructure, and the document does discuss threat modelling initially. It might seem overwhelming to some organisations new to the subject, and that might need some help on what to do first.

I think the document could perhaps do with more cross-referencing to additional information resources elsewhere. Yes, documents can always be improved, and I am sure we will find niggles and faults with use, but threats evolve and so does our knowledge.