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
Newest First  |  Oldest First  |  Threaded View
COVID-19: Latest Security News & Commentary
Dark Reading Staff 8/3/2020
Pen Testers Who Got Arrested Doing Their Jobs Tell All
Kelly Jackson Higgins, Executive Editor at Dark Reading,  8/5/2020
'BootHole' Vulnerability Exposes Secure Boot Devices to Attack
Kelly Sheridan, Staff Editor, Dark Reading,  7/29/2020
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-2020-17364
PUBLISHED: 2020-08-05
USVN (aka User-friendly SVN) before 1.0.9 allows XSS via SVN logs.
CVE-2020-4481
PUBLISHED: 2020-08-05
IBM UrbanCode Deploy (UCD) 6.2.7.3, 6.2.7.4, 7.0.3.0, and 7.0.4.0 is vulnerable to an XML External Entity Injection (XXE) attack when processing XML data. A remote attacker could exploit this vulnerability to expose sensitive information or consume memory resources. IBM X-Force ID: 181848.
CVE-2020-5608
PUBLISHED: 2020-08-05
CAMS for HIS CENTUM CS 3000 (includes CENTUM CS 3000 Small) R3.08.10 to R3.09.50, CENTUM VP (includes CENTUM VP Small, Basic) R4.01.00 to R6.07.00, B/M9000CS R5.04.01 to R5.05.01, and B/M9000 VP R6.01.01 to R8.03.01 allows a remote unauthenticated attacker to bypass authentication and send altered c...
CVE-2020-5609
PUBLISHED: 2020-08-05
Directory traversal vulnerability in CAMS for HIS CENTUM CS 3000 (includes CENTUM CS 3000 Small) R3.08.10 to R3.09.50, CENTUM VP (includes CENTUM VP Small, Basic) R4.01.00 to R6.07.00, B/M9000CS R5.04.01 to R5.05.01, and B/M9000 VP R6.01.01 to R8.03.01 allows a remote unauthenticated attacker to cre...
CVE-2020-8607
PUBLISHED: 2020-08-05
An input validation vulnerability found in multiple Trend Micro products utilizing a particular version of a specific rootkit protection driver could allow an attacker in user-mode with administrator permissions to abuse the driver to modify a kernel address that may cause a system crash or potentia...