Security '03 - Invited Talk
Internet Security: An Optimist Gropes For Hope
Bill Cheswick,
Lumeta
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Table of Contents
Internet Security: An Optimist Gropes For Hope
Firewalls and Internet Security
Most common question from the press:
Universal Answer
Why?
Aug. 1993
In August 1993
CERT advisories: 1994
CERT advisories, 1994
CERT advisories, 1994 (cont.)
Many attacks were theoretical...
...and then they happened...
There are a lot more players, and on average they are a lot less secure
When I started at the Labs (Dec 1987)
Now, everyone is on the Internet
We've been losing ground for decades
Life cycle of a security bug, roughly
Yeahbuttal
Cost vs. Benefits
OTOH, tools we didn't have in 1994
Bright spots, now
I am optimistic. Good security is possible
There are a lot of benefits
Financial business models are working
And Microsoft...
What does good security feel like?
The Morris worm: Nov. 1988
Some facts to keep in mind: economics
Some things we can't fix
Social Engineering
I need to manage expectations here
Software will always have bugs
People pick lousy passwords
Some facts to keep in mind: users are not security experts
Social Engineering (cont.)
Another Problem With Strange Programs
Managing expectations: Denial-of-Service
Wireless passwords
Experts cut corners, too
I cheated on my authentication test
I cheated on my authentication test (cont.)
Some principles and tools
Security strategies
Staying out of the game
Defense in depth
Layered Positive Measures to Assure Against Unauthorized Use
Secure defaults are important
Security doesn't need to be inconvenient
Some solutions: Hardware tokens
One-time Passwords
Authentication
Principles and tools: encryption
Encryption is necessary, but not sufficient
Tools: Trusted Computing Base
Default services—SGI workstation
More default services
If You Don't have a Trusted Computing Base...
Firewalls Perimeter Defenses
Firewalls have their uses
Firewalls: Not a panacea
Anything large enough to be called an "intranet" is probably out of control
PPT Slide
PPT Slide
Some intranet statistics from Lumeta clients
Perimeter defenses don't work if the perimeter is too big
Example: Life Without a Firewall
It can be done
Life without a firewall
We need to be able to trust our hosts
Secure host technology
Secure host technology
Routes to root
root network services
Setuid-root programs
Root: The gatewat to privilige
Setuid-root
So, don't have network services...
So, don't have users...
Get rid of setuid programs if you do have users
Minimize root network services
Three layers of defense we might have
Chroot
Awful stuff you have to do to jail a program
Example: a web server highly-resistant to defacement
Goal
Implementation
Other software I have jailed
Sample message
Sample message
Some jail themselves, or should
Example: Amazon, Fedex, ...
Things are getting better: we have business models
Example: Spook networks
Talk to spooks: they have security experience
Spooks
Spooks...
Ches's wish list
Ches's wish list
More wishes
Ches's wish list
Still theoretical
Conclusion
Questions
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Last changed: 19 Aug. 2003 aw
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