When the Ashley Madison hackers leaked close to 100 gigabytes’ worth of sensitive documents belonging to the online dating service for people cheating on their romantic partners, there seemed to be one saving grace. User passwords were cryptographically protected using bcrypt, an algorithm so slow and computationally demanding it would literally take centuries to crack all 36 million of them.
Now, a crew of hobbyist crackers has uncovered programming errors that make more than 15 million of the Ashley Madison account passcodes orders of magnitude faster to crack. The blunders are so monumental that the researchers have already deciphered more than 11 million of the passwords in the past 10 days. In the next week, they hope to tackle most of the remaining 4 million improperly secured account passcodes, although they cautioned they may fall short of that goal. The breakthrough underscores how a single misstep can undermine an otherwise flawless execution. Data that was designed to require decades or at least years to crack was instead recovered in a matter of a week or two.
The cracking team, which goes by the name “CynoSure Prime,” identified the weakness after reviewing thousands of lines of code leaked along with the hashed passwords, executive e-mails, and other Ashley Madison data. The source code led to an astounding discovery: included in the same database of formidable bcrypt hashes was a subset of 15.26 million passwords obscured using MD5, a hashing algorithm that was designed for speed and efficiency rather than slowing down crackers.