A password-cracking group known as CynoSure Prime cracked 11.2 million Ashley Madisons users passwords. The most common choice among them was 123456 at over 120,000 individual users. The group explains that it was able to crack the bcrypt hashes used to protect the passwords via a roundabout method: attacking the insecure implementation of the MD5 cryptographic hash function. The leaked passwords are for the most part consistent with SplashData’s list of the most common passwords for 2014.”]
Source: https://grahamcluley.com/cracked-ashley-madison-passwords-consistent-years-poor-security/