"Walking" with the SDL – Part 1

Jeremy Dallman here. Back in March I wrote a post about “Crawling” Toward SDL. I used the imagery of learning to “crawl, walk and run” as a way to provide some basic starting points that would move your organization toward implementing a version of Microsoft’s Security Development Lifecycle (SDL).


In this series I am going to talk about “Walking” with the SDL. Walking is the point where your security development practices become a lifecycle – a repeatable, mostly reusable process that makes security a part of your development culture. To relate the analogy to SDL a bit more closely, think of crawling as the “SD” in SDL. For this post, we’ll talk about walking – or adding the “L” in SDL.


I will be covering quite a bit on this topic, so I intend to split it up in to a multi-part series over a few days. I’ll condense it all into one big doc at the end. In Part One, I will review “crawling” and the foundation you need to have in place as well as discuss getting management approval. In Part Two we’ll cover the topic of expanding your security training. In the additional posts, we’ll discuss formalizing requirements, reusing threat modeling and attack surface review data, the importance of final security reviews, and managing post-release documentation. All of these are components to “walking” with the SDL.


Before I jump into detailing what you can do to “walk” with the SDL, let’s look back at a snapshot of what you should already have in place from learning to “crawl.” At a high level, crawling involved three components. Each of these components requires specific activities or tools that your team must implement to begin developing secure code:


1.       Detailed awareness of your architecture and its attack surface.


a.       Threat Modeling


2.       Tools that will perform security analysis on your application.


a.       Strengthen compiler defenses


b.      Use code analysis or static analysis tools such as PREfast, FxCop, AppVerif


c.       Build a strong fuzz testing capability


3.       Results that show how the analysis resulted in improved security


a.       Response planning and response process in place


b.      Use bugs to gather evidence and show that your work improved security



Think of these pieces as the “gross motor skills” you need to start walking. You should already be using these components and have reached a conscious decision to start building a lifecycle around your secure development practices. As you start figuring out how to “walk”, I want to point out that each of the concepts I discuss in this post is a critical component of the Microsoft Security Development Lifecycle. Adopting the SDL in your company involves a combination of integrating the existing SDL principles and the creating of unique requirements and components specific to your environment to build your own Security Development Lifecycle.


With that in place, let’s start talking about what it means to “Walk with SDL.”


Obtain Management Approval/Endorsement


Creating a Security Development Lifecycle will cost time and money. In addition, it will likely require some process changes. In most organizations, this change will not happen unless you obtain the management approval and endorsement necessary to compel the organization to act.


The key to successfully pitching SDL to your management can be found in the data you have been accumulating during the “crawl” phase. As you may recall from my crawling post, the simplest way to create evidence that clearly illustrates improved application security is to “mine” the data from your bug database. Connecting those bugs to known security vulnerabilities or to what would have been bad security issues that were avoided by fixing them in development is a powerful story. Of course your pitch should include other necessary components like anticipated costs, new software acquisition, possible vendor and consulting contracts and anticipated return on investment.


However, the heart of your argument will be the story you tell. The story is quite simply “If we hadn’t done this basic work in security, here is what we would have missed and how much it would have hurt…” followed by “if we continue to expand our security practices and make them a part of our process, we can better predict measurable security improvements that reduce the likelihood of future risks.”


The new SDL website [http://www.microsoft.com/sdl] provides some valuable reference material on the Business Case for SDL. I would recommend that looking through that information for some good supporting material. In Part Two, I will discuss expanding your security training as another component of “walking” with SDL.



I’d like to hear if anyone is using the concept of “crawling” and “walking” to implement SDL in your company.


?        What unique challenges are you facing as you try to push for SDL adoption?


?        What have you used to successfully communicate the importance of security to your management?


Join the conversation

  1. TonyD

    Great set of posts, looking forward to Running.  By the way, the link to the Crawling blog entry is broken.

  2. sdl

    Thanks for catching that Tony. I have fixed the link to the "crawl" post.

  3. Philip.Agcaoili

    I’ll add one more topic to Walking in the SDL–Integration with prevailing business lifecycles.

    I’ve had a lot of success embedding security steps into existing lifecycles used by Project Management (PMO) and Software Development organizations (SDLC).

    You end of killing two needs through this integration since it’ll require management buy-in and now you’ll get security integration.

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