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I wrote BozoCrack to show why plain MD5 is a horrible way to hash passwords.

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Re: I wrote BozoCrack to show why plain MD5 is a horrible way to hash passwords.

#21

Post by carbocation »

seabee wrote: post #10
carbocation wrote: post #8

Earlier quoted context omitted.

If using your own salt is all you do, you'd still be susceptible to easy statistical attacks once someone compromises your database. But, yes, they probably wouldn't be available on google.

If using MD5 is all you do, you'd still be susceptible to brute force attacks . MD5 is a really fast hash to compute, salting or not. The solution is to pick a better algorithm and learn how to use it securely. That probably won't happen unless all the ridiculous PHP 'security' tutorials are erased from the history of the internet and only correct methods are shown.

Definitely. I'm just saying that I could recover the common passwords with a 486 instead of a GPU :)

Re: I wrote BozoCrack to show why plain MD5 is a horrible way to hash passwords.

#23

Post by phzbOx »

To the other posts saying how MD5 is not bad and/or it's stupid to use MD5 without salt (or whatever):

See this script more as a fun little hack rather than a "Formal proof". Thanks aparadja for sharing. That being said, using MD5 without salt is asking for trouble. I mean, I know security is usually just a time vs $ vs quality problem, but it costs almost nothing more to add a salt in front of the password. Why not do it?

Re: I wrote BozoCrack to show why plain MD5 is a horrible way to hash passwords.

#24

Post by jeffreymcmanus »

Cushman wrote: post #22

Seriously? Who is still using md5? There are strong hashing libraries for like every language. Anyone reading this uses md5? Can we find these people and just let them know?

This kind of work is one way we let people know.

Re: I wrote BozoCrack to show why plain MD5 is a horrible way to hash passwords.

#25

Post by aparadja »

TillE wrote: post #20
aparadja wrote: post #14

Earlier quoted context omitted.

Perhaps I should have written it as "unsalted MD5" instead of "plain MD5" to avoid confusion. Unsalted MD5, in my opinion, is horrible. MD5 plays it's part in the mess: it's quick to calculate, which means that anybody can churn out huge lookup databases. Missing salts make those databases universally usable.

> huge lookup databases "Huge" being the key word here. Try searching for the md5sums of arbitrary 8-character alphanumeric passwords. You won't find many results. 62^8 is a big number.

Covering the whole solution space would be an enormous (as compared to just huge) undertaking. But if you limit yourself to the types of passwords people usually use, you can prune it down quite a bit.

The currently available databases are surprisingly large, even if not in the scale of 62^8. Consider a random pick from decrypt.fr: "phytostrote972". It's far from a random string, but not exactly a trivial one either.

Re: I wrote BozoCrack to show why plain MD5 is a horrible way to hash passwords.

#26

Post by dhimes »

seabee wrote: post #10
carbocation wrote: post #8

Earlier quoted context omitted.

If using your own salt is all you do, you'd still be susceptible to easy statistical attacks once someone compromises your database. But, yes, they probably wouldn't be available on google.

If using MD5 is all you do, you'd still be susceptible to brute force attacks . MD5 is a really fast hash to compute, salting or not. The solution is to pick a better algorithm and learn how to use it securely. That probably won't happen unless all the ridiculous PHP 'security' tutorials are erased from the history of the internet and only correct methods are shown.

Do you have a reference that you would consider "the minimum you should know?" And, perhaps, maybe one somewhat better than that one? TIA.

Re: I wrote BozoCrack to show why plain MD5 is a horrible way to hash passwords.

#28

Post by tptacek »

phzbOx wrote: post #23

To the other posts saying how MD5 is not bad and/or it's stupid to use MD5 without salt (or whatever): See this script more as a fun little hack rather than a "Formal proof". Thanks aparadja for sharing. That being said, using MD5 without salt is asking for trouble. I mean, I know security is usually just a time vs $ vs quality problem, but it costs almost nothing more to add a salt in front of the password. Why not…

Using MD5 with a salt is asking for trouble.

Using SHA256 with a salt is asking for trouble.

Use bcrypt, scrypt, or PBKDF2. Do not DIY your password hash.

Re: I wrote BozoCrack to show why plain MD5 is a horrible way to hash passwords.

#29

Post by tptacek »

dhimes wrote: post #26
seabee wrote: post #10

Earlier quoted context omitted.

If using MD5 is all you do, you'd still be susceptible to brute force attacks . MD5 is a really fast hash to compute, salting or not. The solution is to pick a better algorithm and learn how to use it securely. That probably won't happen unless all the ridiculous PHP 'security' tutorials are erased from the history of the internet and only correct methods are shown.

Do you have a reference that you would consider "the minimum you should know?" And, perhaps, maybe one somewhat better than that one? TIA.

Yes: http://codahale.com/how-to-safely-store-a-password/

This is the answer to this question. You should bookmark it and share it with your peers when this question inevitably comes up on another thread.

Re: I wrote BozoCrack to show why plain MD5 is a horrible way to hash passwords.

#30

Post by aparadja »

Cushman wrote: post #22

Seriously? Who is still using md5? There are strong hashing libraries for like every language. Anyone reading this uses md5? Can we find these people and just let them know?

Wasn't MtGox, the Bitcoin exchange that was hacked a while ago, using md5?
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