Well, after the last blog I wrote (a year ago, embarassing, I know), it seems that SONY's PS3 has delivered yet again on it's pre-release promises of computational power.
In my previous blog spot, I wrote about the PS3's ability to crack MD5 hashes. Of cource, one machine could only (!) do 1000 times better than an Intel based processor, yielding the attack probably too time-consuming to be a real threat. But, as I predicted, a real threat has appeared.
Combining the computational force of 200 of these machines, attackers managed to break one of the MD5 algorithms used by Equifax and forge an invalid certificate from a valid provider. More details can be found here, here and here.
But the problem is not the attack itself, but rather the downplay from a number of parties, including the researches that performed the attack, and Microsoft. They are basing their evaluation of the risk to the fact that in order for black-hat attackers to use the breakthrough they need to have the cryptographic backround. And of course, we know how dumb hackers are when it comes to monetary gain...
A remedy of sort is not using MD5 as a hashing algorithm for SSL. It is well known that SSL uses two (primary) methods for doing hashing, MD5 and SHA1. For those who might be a bit worried, simply trust (for the time being) encrypted pages that use certificates that either use only SHA1 or use both SHA1 and MD5. It also has to be noted that in order for an attack to be succesful, not only does an attacker have to create a forged SSL certificate, but also redirect a victim to a malicius server. And we know that can't happen (remember the Kaminsky attack? 25 per cent of the worlds DNS servers still remain unpatched!)
To keep things short, I said it a year ago, I'll say it again. I may not be a guru in the field, but I know enough to understand that week algorithms should be made obsolete. SHA1 may be a remedy for the time being (as it is more secure than MD5 currently), but remember, it has not been ckacked, but it has been broken. Serious businesses should move to more secure algorithms, as if they wait for the tidal wave of security failure, I'm pretty sure they will go down with their ship.