Black hats are just as blithe about the passwords they use as the rest of the world, according to a bit of research by security outfit Avast.

The anti-virus company's Antonín Hýža, writes here that after he'd built a dictionary of hacked hackers' passwords, the most common password was “hack”.

Hýža says his work began because he had the job of decoding a PHP shell without the key. Rather than try to brute force the shell, he figured that building a dictionary of hackers' passwords would accelerate the process. So he raided the company's samples of backdoors, bots and shells, some of which “are protected with a password encoded in MD5, SHA1 or in plain text”.

With 40,000 samples in hand, Hýža said, “nearly 2,000 were unique and 1,255 of those were in plain text”. Short passwords hashed in MD5 were easy to crack, and yielded another 348 samples, and the total is what he analysed to build his dictionary. Here's some other highlights:

59 per cent of passwords used only characters – no numbers or special symbols

Only six per cent included non-alphanumeric character;

Many of the samples in the analysis used default passwords like r57, c99, password or yourpass.

Hýža says the dictionary also yielded a couple of handy character sets for when he had to apply brute force to a password: acdehiklmnorstu01234579!-.@_ and acdehiklmnorstubgpxyw0123456789!-.@_#$+*{space} – and interestingly, when he had to resort to brute force, in all cases the passwords were six characters or fewer.

Perhaps Vulture South's favourite example of passwords Hýža found was lol dont try cracking 12 char+ – which was stored in plain text. ®