Fergie's Tech Blog

Law Enforcement Appliance Subverts SSL

Ryan Singel writes on Threat Level:

That little lock on your browser window indicating you are communicating securely with your bank or e-mail account may not always mean what you think its means.

Normally when a user visits a secure website, such as Bank of America, Gmail, PayPal or eBay, the browser examines the website’s certificate to verify its authenticity.

At a recent wiretapping convention however, security researcher Chris Soghoian discovered that a small company was marketing internet spying boxes to the feds designed to intercept those communications, without breaking the encryption, by using forged security certificates, instead of the real ones that websites use to verify secure connections. To use the appliance, the government would need to acquire a forged certificate from any one of more than 100 trusted Certificate Authorities.

The attack is a classic man-in-the-middle attack, where Alice thinks she is talking directly to Bob, but instead Mallory found a way to get in the middle and pass the messages back and forth without Alice or Bob knowing she was there.

The existence of a marketed product indicates the vulnerability is likely being exploited by more than just information-hungry governments, according to leading encryption expert Matt Blaze, a computer science professor at University of Pennsylvania.

“If company is selling this to law enforcement and the intelligence community, it is not that large a leap to conclude that other, more malicious people have worked out the details of how to exploit this,” Blaze said.

posted by Fergie @ 3/24/2010 01:54:00 PM