Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Perimeter

10/23/2009
12:09 PM
Gadi Evron
Gadi Evron
Commentary
Connect Directly
Twitter
LinkedIn
RSS
E-Mail
50%
50%

Trusting Trust

An old and respected paper about compilers teaches us a lot about network security architecture.

An old and respected paper about compilers teaches us a lot about network security architecture.When I recently blogged about how Web ads can be compromised to infect users who visit famous Websites, I mentioned a key paper in security history, "Reflections on Trusting Trust," by Ken Thompson.

"In 1984, Ken Thompson, the co-inventor of Unix, wrote a paper for the ACM called 'Reflections on Trusting Trust.' In it, he stipulated how he could insert a backdoor into the compiler so that even if your code is safe, after being compiled it will get back-doored.

While his paper is about compilers, the concept is trust. How far can you trust anything? How far can what you trust, in turn, trust anything further down the line?

If you write your own programs, then you can be reasonably sure they have no backdoor. Do you also write your own compiler? How about the operating system? The motherboard? The CPU?

There's no end to trust. No matter how paranoid you are, eventually you have to take a leap of faith."

Here's how this concept affects network architecture security: When you build a network, you may invest in high walls -- strong outward defenses. Is there any reason to invest in defenses inside that circle of high walls?

Security is not just a profession of risk and trust, but also of cost and benefits. If you had 100 percent security -- which isn't possible, of course -- would you benefit at all by adding security inside the walls? Would spending more resources make any sense?

We can always use more security if we can afford it and it's indeed useful. We can't ever tell what did get through our first lines of defense, or what we may not know we need to defend against.

So add more defenses, but use common sense.

While layered defense is a solid strategy, another option is instead investing your resources where you see the most risk. So if you already filter the Web well or if infected machines can't communicate with the world, anyway, you may not need to put additional security resources there.

Both of these approaches are extreme archetypes -- the best bet is somewhere in the middle. Trusting trust says we will always have another layer to add.

I try and subscribe to the "always add more security" approach, but I make sure I model it after my risk analysis so that it's applied correctly.

Post a comment if you have had any experiences with this.

Follow Gadi Evron on Twitter: http://twitter.com/gadievron

Gadi Evron is an independent security strategist based in Israel. Special to Dark Reading. Gadi is CEO and founder of Cymmetria, a cyber deception startup and chairman of the Israeli CERT. Previously, he was vice president of cybersecurity strategy for Kaspersky Lab and led PwC's Cyber Security Center of Excellence, located in Israel. He is widely recognized for ... View Full Bio

 

Recommended Reading:

Comment  | 
Print  | 
More Insights
Comments
Oldest First  |  Newest First  |  Threaded View
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Current Issue
Special Report: Computing's New Normal, a Dark Reading Perspective
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
The Threat from the Internetand What Your Organization Can Do About It
The Threat from the Internetand What Your Organization Can Do About It
This report describes some of the latest attacks and threats emanating from the Internet, as well as advice and tips on how your organization can mitigate those threats before they affect your business. Download it today!
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-11583
PUBLISHED: 2020-08-03
A GET-based XSS reflected vulnerability in Plesk Obsidian 18.0.17 allows remote unauthenticated users to inject arbitrary JavaScript, HTML, or CSS via a GET parameter.
CVE-2020-11584
PUBLISHED: 2020-08-03
A GET-based XSS reflected vulnerability in Plesk Onyx 17.8.11 allows remote unauthenticated users to inject arbitrary JavaScript, HTML, or CSS via a GET parameter.
CVE-2020-5770
PUBLISHED: 2020-08-03
Cross-site request forgery in Teltonika firmware TRB2_R_00.02.04.01 allows a remote attacker to perform sensitive application actions by tricking legitimate users into clicking a crafted link.
CVE-2020-5771
PUBLISHED: 2020-08-03
Improper Input Validation in Teltonika firmware TRB2_R_00.02.04.01 allows a remote, authenticated attacker to gain root privileges by uploading a malicious backup archive.
CVE-2020-5772
PUBLISHED: 2020-08-03
Improper Input Validation in Teltonika firmware TRB2_R_00.02.04.01 allows a remote, authenticated attacker to gain root privileges by uploading a malicious package file.