Monthly Archives: November 2014

Security Advice from the US Department of Justice: Include “Back Doors” to enable Monitoring

November 17th, 2014
DOJ recommends back doors.  How smart is this?

DOJ recommends back doors. How smart is this?

Security Advice from the US Department of Justice: Include “Back Doors” to enable Monitoring.  How smart is this?

By Alan Grau, Icon Labs

In a recent statement issued by the US Department of Justice, device manufacturers are encouraged to include “back doors” in devices to allow law enforcement to perform surveillance in the electronic world. Adding a back door can neutralize all other security measures; back doors should not be added! 

Back doors are nothing new in the world of computing.  Hackers have found, and exploited, back doors in WiFi routers and IP cameras.  In the early 1980s, Ken Thompson created a simple back door that he could have inserted into every Unix system on the planet by a cleverly disguised hook in the lowest levels of the compiler’s code generation module.  I even worked on a product early in my career that included a back door to allow developers access to any system in the field for debugging.  The intent was to remove the back door prior to shipment of production units, but it’s easy for features such as this to “accidently” slip into production code, leaving a gaping hole in the security of a product. 

This DoJ recommendation is reminiscent of my first programming job out of college.  As a fresh, bright eyed young programmer working for AT&T Bell Labs, I was working on software for their 5ESS switch, the backbone switching systems for many telephone systems worldwide.  Our team worked on the Call Monitoring subsystems, which allowed collection of phone call logs on specific phone numbers.  This allowed law enforcement to collect daily reports of everyone who was called by or who called a specific phone number.  We also supported a feature enabling law enforcement to listen in live to any call from a specified phone number. 

AT&T Bell Lab

This feature was, according to the sales people, a big selling point in the former Soviet Union, but was not included in domestic products because of conflict with privacy laws.

The new DOJ recommendation not only raises concerns over possible privacy abuses, but creates an easily exploited security hole.  With the distributed nature of devices today, devices are certain to come under cyber-attack.  For consumer devices, hackers are able to access the firmware of the device.  With the firmware in hand, a skilled hacker can disassemble and reverse engineer the code, allowing them to find back doors. 

Devices are also vulnerable to inside attacks by those with knowledge of back doors.  A single disgruntled employee or other bad actor can utilize the information obtained via off the back door to cause serious harm.  Unfortunately, once disclosed, most back doors are not readily disabled, leaving a vast number of devices vulnerable.    

While there is a legitimate need for the DOJ to monitor communication, within the bounds of our legal system, in this day of digital communication, we must not sacrifice security to do so. Regardless of the other security measures taken, don’t add back doors!

Alan Grau is President and co-founder of Icon Labs, a leading provider of security software for embedded devices. He is the architect of Icon Labs’ award winning Floodgate Firewall. Alan has 20 years of embedded software experience. Prior to founding Icon Labs he worked for AT&T Bell Labs and Motorola. Alan has an MS in computer science from Northwestern University. You can reach him at