This tool bruteforces a selected user using su and as passwords: null password, username, reverse username and a wordlist (top12000.txt).
You can specify a username using -u <username> and a wordlist via -w <wordlist>.
By default the BF default speed is using 100 su processes at the same time (each su try last 0.7s and a new su try in 0.007s). It needs 143s to complete.
You can configure these times using -t (timeout su process) and -s (sleep between 2 su processes).
Fastest recommendation: -t 0.5 (minimun acceptable) and -s 0.003 ~ 108s to complete.
./suBF.sh -u <USERNAME> [-w top12000.txt] [-t 0.7] [-s 0.007]