BERLIN--A key piece of Internet technology that banks, e-commerce sites, and financial institutions rely on to keep transactions safe suffers from a serious security vulnerability, an international team of researchers announced on Tuesday.

They demonstrated how to forge security certificates used by secure Web sites, a process that would allow a sufficiently sophisticated criminal to fool the built-in verification methods used by all modern Web browsers--without the user being alerted that anything was amiss.


The problem is unlikely to affect most Internet users in the near future because taking advantage of the vulnerability requires discovering some techniques that are not expected to be made public (Editor's Note: too late, cat's outta the bag..now that they know it can be done, it'll be done again) as well as overcoming engineering hurdles: performing the initial digital forgery consumed approximately two weeks of computing time

(Editor's Note: yeah, the "initial" digital forgery took that long, but now that they know how to do it how long would it take? Besides, the potential monetary reward for two weeks work is huge ) on a cluster of 200 PlayStation 3 consoles.

In addition, a criminal needs to find a way to reroute traffic from a legitimate Web site to his own, perhaps through techniques that have become well-known in the last few years. (Editor's Note: What? It's unlikely to happen unless hackers use "well-known techniques?" They're kidding right? That's what the kid with the paper is selling, but I'm not buyin' it.)

Yet if one group can do it today, others eventually will. (Editor's Note: at least that line is clearly stated) "We have a proof-of-concept that allows us to impersonate any supposedly secure Web site on the Internet," said David Molnar, a doctoral student in computer science at the University of California at Berkeley.

Molnar and six other researchers presented their findings during an afternoon session of the Chaos Computer Club's annual conference here on Tuesday. Other team members include Jacob Appelbaum and Alexander Sotirov.

Their work has focused on finding vulnerabilities in a technology known as Secure Sockets Layer, or SSL, which was designed to provide Internet users with two guarantees: first, that the Web site they're connecting to isn't being spoofed, and second, that the connection is encrypted and is proof against eavesdropping. SSL is used whenever a user navigates to an address beginning with "https://". SSL certificates essentially stand for the claim that, for instance, etrade.com actually belongs to E-Trade Inc., and is not being operated by a thief hoping to steal account passwords.

Most browsers indicate that SSL is active by displaying a small padlock icon. (see pic on right) An attack using a forged authentication certificate--which is what the researchers say they have done--is insidious because the browser can't detect it and the padlock icon would still appear.

Unlike most security issues, this problem cannot be fixed with a simple software update. "The bug is not in anyone's software," Sotirov said. "It's not the browser that's at fault. The browser does exactly what it's supposed to do... The problem is that what it's supposed to do is wrong."

The attack exploits a mathematical vulnerability in the MD5 algorithm, one of the standard cryptographic functions used to check that SSL certificates (and thus the corresponding Web sites) are valid. This function has been publicly known to be weak since 2004, but until now no one had figured out how to turn this theoretical weakness into a practical attack.

An SSL certificate is a small file that ties a real-world corporate identity to a Web site address and a corresponding public encryption key. This is presented to a private certificate authority firm, which is supposed to verify the link between identity and domain name and then cryptographically "sign" the certificate to vouch for it.

The problem arises when someone else is able to forge the same signature... continue reading at CNET News