I doubt dropbox was hacked. It also doesn't look like a dictionary attack.
It seems more likely that a third-party website wasn't storing passwords correctly, was hacked, and this is the list of users that use a single password for everything.
It seems more likely that a third-party website wasn't storing passwords correctly, was hacked, and this is the list of users that use a single password for everything.
Bille97... Billel... Billen... Billet... Billew...
Isn't it unlikely that so many alphabetically-similar accounts from the third-party site would use the same password for dropbox?
-> % cat 1000000\ email\ list.txt | sed 's/, */\n/g' | grep "@"| sort | uniq | wc -l
835694
-> % cat 1000000\ email\ list.txt | sed 's/, */\n/g' | grep "@"| sort | uniq | grep -i "^b[e-i]" | wc -l
11160
irb(main):001:0> (835694.0 / 11160) * 400
=> 29953.189964157707