Re:Disqus cracked – Security flaw reveals users’ e-mail addr...
by amckenna on Tuesday December 10, 2013 @03:52PM
(#6883612)
Another solution would be for these services to use something with a greater work factor than MD5. When a typical user can brute force MD5s at a rate of 8.5 billion per second with AMD HD7970 graphics card then it's time to use a different hashing algorithm. Something like scrypt or bcrypt with a larger work factor would make these attacks much harder and more expensive, while leaving the fundamentals of the system the same.
http://hashcat.net/oclhashcat/ https://www.tarsnap.com/scrypt.html https://en.wikipedia.org/wiki/Bcrypt
I reported a username -> plaintext email vuln to Disqus earlier this year and they were very prompt in patching it, I wouldn't criticize them for this at all as this a very common issue across most blog comment systems.
Would be nice to change how Gravatar works, but it's fairly fundamental. I think if you want your email to be private you should probably be registering temporary ones or using the + aliases like gmail offers to avoid these kinds of hash-cracking attacks.