Analytics

2/29/2016
10:30 AM
Jeff Schilling
Jeff Schilling
Commentary
Connect Directly
Facebook
Twitter
LinkedIn
RSS
E-Mail vvv
50%
50%

Measuring Security: My Dwell Time Obsession

How I discovered the critical metric to fuel my drive to create the most secure environment possible.

Throughout my military career, I had two- and three-star generals ask — no, demand — that our security and operations center have measurable cybersecurity metrics. They’d challenge me with the same gamut of questions: “How do you know we are making a difference? Are we getting any better? How do we calculate our return on investment if we don’t know what to measure?” 

I retired from the U.S. Army in 2012. I was never able to answer any of those demands for “good” cybersecurity metrics.

One of the metrics I talked myself out of providing was our number of infected hosts. Is a low number good or bad? If it is low, I am paranoid that I am missing threat activity. If the number is high, there’s a bigger problem at hand. No matter the number, you can never find the denominator (i.e., the actual number of infected hosts). 

From there, I considered another metric: number of security events. This caused me concern as well. Most complex environments detect billions of daily security events. It is impossible to characterize them as true positives or false positives. Plus, I can’t be sure of the number of dreaded true negatives. How many events evaded detection by our security sensors?

Nothing felt informative or effective.

After I left the military, I finally figured it out. I was fortunate enough to manage an incident response and forensics team. Everything a forensics teams does in their investigations is in the context of the Kill Chain. This is the seven-step sequence of events that must occur for a threat actor to achieve their objectives (e.g., steal or destroy data). 

While examining the Kill Chain, the idea dawned on me. I could measure the one variable that a threat actor had to have in order to be successful: dwell time in the network. I needed to eliminate or reduce the amount of time they have to complete the Kill Chain. That’s it. If I could limit dwell time, the threat actor would not have what they needed to progress through the Kill Chain.

Dwell time, which is the duration a threat actor has in an environment before they are detected or eliminated by the security team, is something I could measure fairly accurately with a good forensics investigation.

There are a number of well-known dwell time benchmarks to get a good baseline to measure against. Most of the major annual cybersecurity reports now cite the average dwell time number as being over 200 days. We can do better. We must do better.

With this renewed focus, I centered my security strategy around reducing dwell time by: 

  • Leveraging hardened CIS server builds
  • Building an aggressive patching program focused on the most likely targeted servers in our data centers
  • Using on-access scans for anti-malware tools
  • Integrating traffic-shaping at that edge, with IP reputation management, to remove the noise for network intrusion detection and Layer 7 inspection
  • Deploying a ‘zero-trust’ model in provision servers (i.e., only ports and protocols required for operation are open)
  • Leveraging a SIEM with great correlation 

Dwell time is my obsession. Through diligence and careful process, we continue to see this number drop in our customer environments. This change in thinking rallies the team around one standard (measuring the amount of time from detection to eradication) that is quantifiable and can be leveraged to calculate the effectiveness of a security strategy and overall posture.

No metric is perfect. But any other approach has too many unknowns that will overrun you with false positives. Until a new standard is found, dwell time will continue to be my obsession.

Related Content:

 

Interop 2016 Las Vegas

Find out more about security threats at Interop 2016, May 2-6, at the Mandalay Bay Convention Center, Las Vegas. Register today and receive an early bird discount of $200.

Jeff Schilling, a retired U.S. Army colonel, is Armor's chief security officer. He is responsible for the cyber and physical security programs for the corporate environment and customer-focused capabilities. His areas of responsibilities include security operation, governance ... View Full Bio
Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
RyanSepe
50%
50%
RyanSepe,
User Rank: Ninja
2/29/2016 | 12:41:25 PM
False Negatives
"Plus, I can't be sure of the number of dreaded true negatives. How many events evaded detection by our security sensors?"

You may want to update with false negatives.
Veterans Find New Roles in Enterprise Cybersecurity
Kelly Sheridan, Staff Editor, Dark Reading,  11/12/2018
Understanding Evil Twin AP Attacks and How to Prevent Them
Ryan Orsi, Director of Product Management for Wi-Fi at WatchGuard Technologies,  11/14/2018
7 Free (or Cheap) Ways to Increase Your Cybersecurity Knowledge
Curtis Franklin Jr., Senior Editor at Dark Reading,  11/15/2018
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Flash Poll
Online Malware and Threats: A Profile of Today's Security Posture
Online Malware and Threats: A Profile of Today's Security Posture
This report offers insight on how security professionals plan to invest in cybersecurity, and how they are prioritizing their resources. Find out what your peers have planned today!
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2018-19355
PUBLISHED: 2018-11-19
modules/orderfiles/ajax/upload.php in the Customer Files Upload addon 2018-08-01 for PrestaShop (1.5 through 1.7) allows remote attackers to execute arbitrary code by uploading a php file via modules/orderfiles/upload.php with auptype equal to product (for upload destinations under modules/productfi...
CVE-2008-7320
PUBLISHED: 2018-11-18
** DISPUTED ** GNOME Seahorse through 3.30 allows physically proximate attackers to read plaintext passwords by using the quickAllow dialog at an unattended workstation, if the keyring is unlocked. NOTE: this is disputed by a software maintainer because the behavior represents a design decision.
CVE-2018-19358
PUBLISHED: 2018-11-18
GNOME Keyring through 3.28.2 allows local users to retrieve login credentials via a Secret Service API call and the D-Bus interface if the keyring is unlocked, a similar issue to CVE-2008-7320. One perspective is that this occurs because available D-Bus protection mechanisms (involving the busconfig...
CVE-2018-19351
PUBLISHED: 2018-11-18
Jupyter Notebook before 5.7.1 allows XSS via an untrusted notebook because nbconvert responses are considered to have the same origin as the notebook server. In other words, nbconvert endpoints can execute JavaScript with access to the server API. In notebook/nbconvert/handlers.py, NbconvertFileHand...
CVE-2018-19352
PUBLISHED: 2018-11-18
Jupyter Notebook before 5.7.2 allows XSS via a crafted directory name because notebook/static/tree/js/notebooklist.js handles certain URLs unsafely.