For those interested,
Sean Gorman (who now has his Ph.D.) did his dissertation on uncovering vulnerabilities in the US’s Internet and fiber optic backbone (among others). His research drew the attention of federal authorities and ultimately forced him to create 2 versions of his dissertation - an unclassified version and a classified version.
Here’s the link from the Washington Post:
http://www.washingtonpost.com/ac2/wp-dyn/A23689-2003Jul7
You can also see some of his research at the links below:
http://www.fcw.com/solutions/presentations/cio/2003/5/msn.pdf
http://policy.gmu.edu/imp/research/Cyber_threat_paper.pdf
If anyone knows where the vulnerabilities are (at least with respect to the physical infrastrcture) it’s Sean Gorman.