Transvasive Security

the human factor

Measuring Security Effectiveness

The last “security” talk I’m cataloging this week is one that Sean Scott and I gave in some form a few times, based on Sean’s work to measure the effectiveness of our Application Security Team.

From the abstract:

How do you measure the effectiveness of security? How can you prove that security is a good investment?

In 2016, we established a security function within software engineering at Express Scripts. Taking a software engineering approach to security, we created testing services, hired developers to build tools and conduct secure code reviews, and established the AppSec Defenders training program.

In 2020, we challenged ourselves to evaluate the effectiveness of our application security program by analyzing the impact of our team’s services on pen-test findings. A 3-month data analysis found that development teams working with us fixed their pen-test findings faster and had significantly fewer new pen-test findings than teams we didn’t work with. We continued the analysis with a randomized controlled trial: by assigning new teams to work with us (or not), we have created an experiment to test the impact of our program.

We will share the specific application security practices that we believe led to these improved outcomes, how we adjusted our services in response to our findings, a recently published industry report that supports our conclusions, and the current status of our randomized controlled trial, which we expect to complete in the first half of 2021.


This was an ambitious project, and we worked hard to create a rigorous study, grounded in evidence. There were a few key findings:

  1. There was a significant improvement in the performance of the development teams we worked with, which we expected. The magnitude of the impact was large enough that we estimated we more than paid for our entire team with just the reduction in time spent fixing bugs after the fact, without considering the reduction in security risk.
  2. Surprisingly, the level of engagement with our team had much less impact than whether or not a development team was working with us. We used this insight to scale back the amount of time we spent working with individual teams in order to work with a greater number of teams, to increase our overall impact.
  3. Our strategies: using DAST + SAST, frequent scanning, and integrating SAST with our CI/CD pipeline for a steady scan cadence, were found to be the top 4 factors in improving remediation times by the Cyentia/Veracode State of Software Security Volume 11 report. This was quite validating for us, as we had taken this approach before the data was available.


We presented the talk on four different occasions, all virtual due to the pandemic:

  • In August 2020, I gave a brief presentation based on our work at the SIRAcon Day 2 lightning round (Slides).
  • Later in 2020, we gave the full presentation at an internal company technical conference. One attendee suggested we present at an external security conference, so we did!
  • In May 2021, we presented together at Secure360. Slides from that event are here.
  • Finally, in October 2021, we presented again at the ISC2 Security Congress, with a few new slides, copy here.

Note: the SIRAcon video is only available to SIRA members.

A Footnote

Finally, a footnote: this work was inspired in part by an earlier study we performed, where we measured the impact of static code analysis scanning on security bugs in software. What we found was that simply giving teams the tool or SAST reports didn’t reduce the number of security bugs. Making SAST testing “high” failures break the builds (which we encouraged teams to adopt voluntarily) or pushing teams to resolve open high findings (which was less voluntary) was necessary for improvement, as we later showed.


Secure360 2018

As mentioned in my last post, I’ve been cataloging my past talks and am posting the “missing” ones here.

Back in 2018, I spoke at Secure360 on “Integrating Security into Emerging DevOps”. This was a brand new talk, based on my experiences from my first three years running Application Security at Express Scripts:

Imagine building a software security practice. Now imagine building a security practice while your organization is modernizing software engineering, shifting from Waterfall to modern Agile/CI/DevOps.

Teams are excited. Agile means more freedom, less bureaucracy, less security. Security rules are blockers; they are preventing software from being written and deployed, and are problems to be removed. The security team resists, worrying that agile will mean only that security bugs are pushed into production faster.

In fact, modern software engineering and security are entirely compatible; the rigor and discipline that comes with DevOps supports strong security. The challenge is that security must evolve as the organization evolves, and must be part of the natural flow of how engineers develop software today.

This session will present solutions for building security in to a modern software engineering organization that reduce friction, making the engineers happy, and reduce security issues, making the security team happy. By understanding the motivation and habits of software engineers, we can design security controls that satisfy both groups.

I’ve been meaning to post this talk for some time, as it was well received and a good case study on integrating security into a software engineering practice. Much like when Herbie Hancock hired funk musicians to play Jazz on his fusion album Head Hunters, we hired people with a software engineering background to do security; our security engineers were developers, and our application security testing team had a QA background. In this way, we were able to extend the software engineering practice into security and avoid much of the conflict that can occur when staffing AppSec with traditional security professionals.

Slides from that talk are available here.


Past Talks

This week I’ve been looking through and cataloging my past presentations, and found a few older ones that were never posted here or at

Here are brief notes and slides from these past talks:

University of MN

I presented a version of my Behavioral Information Security talk, tailored for an information security class at the Carlson School of Management, on February 13, 2012.


On April 16, 2013, I presented a version of my Information Safety talk that I originally gave at SIRAcon to the ISSA Security Education and Awareness Group, along with the Information Safety Basics slides I’d developed.

Secure360 2013

In May 2013, I gave an updated version of the Behavioral Threat Modeling talk I originally gave at the ISC2 Security Congress in 2012.

Secure360 2017

Finally, I spoke at Secure360 2017 on “Practical Identity Access Management”, originally given at CyberSecureGov. I was later invited to present the talk again at the first (and last) Secure360 conference in Milwaukee, WI in 2018. (slides)

I’ll be posting some additional talks with new materials separately.