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Zxcvbn: realistic password strength estimation

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Re: Zxcvbn: realistic password strength estimation

#101
post #73

Earlier quoted context omitted.

My solution so far is: cat /dev/urandom|base64|tr -d '/+'|head -c10 Nearly every site supports a-z,A-Z,0-9 at 10 characters

Have you used pwgen before?

apg is another good one, and if you call it with no arguments, it defaults to 'complex passwords with memorable syllables' (eg "zuWeebsIbep3 (zu-Weebs-Ib-ep-THREE)").

Re: Zxcvbn: realistic password strength estimation

#102
post #82

Earlier quoted context omitted.

My biggest pet peeve is how no one explains their password constraints until you break one of them.

I recently did a password change for some Apple site (iTunes, I think) and they handled this nicely. They put up a box beside the password field that listed the requirements, and as soon as I started typing it started dynamically changing the list to mark the requirements that my current entry did not meet.

I just went through the iTunes "forgot my password" process and had a different experience. According to that box to the side, my new password passed all their requirements, yet on submit it kept rejecting it. I finally got it to accept a password when I stopped trying to use spaces. Are there other characters their back end rejects that the front end allows?

Re: Zxcvbn: realistic password strength estimation

#103

$^$^$^_ = crack time 26 days $^$^$^i = crack time 3 months $^$^$^z = crack time 5 years Should the result vary so widely given the arguably minor variation?

$^$^$^_ and $^$^$^z are both recognized by zxcvbn as bruteforce regions. it reports the entropy as:

n log (c)

for a length-n password with symbol space c. the huge difference in crack time is because zxcvbn is using c==33 (symbols only) for $^$^$^_ and c==59 (symbols + a-z) for $^$^$^z

$^$^$^i is in the middle -- 'i' is considered a dictionary match, the rest is c==59 bruteforce.

the bigger problem is $^$^$^ isn't recognized as a pattern, but i'm working on ways to improve bruteforce estimation too. good example!

Re: Zxcvbn: realistic password strength estimation

#105
post #88

Earlier quoted context omitted.

Does that break more then md5? I thought it was well known that md5 was a bad password hash algorithm.

I don't know why an application couldn't also attack other hashing algorithms. It's just about brute force creating lots of hashes. This app also uses GPUs to brute force TrueCrypt: http://www.golubev.com/igprs/

Because algorithms like bcrypt have a computational difficulty parameter. You can dial it up so that every check takes something ridiculous. Now instead of brute forcing all of those possibilities in 10 days, it's 1000 centuries.

Re: Zxcvbn: realistic password strength estimation

#106

Length beats entropy every time. Steve Gibson has covered this before. https://www.grc.com/haystack.htm

Steve Gibson is pretty much clueless. (http://attrition.org/errata/charlatan/steve_gibson/)

SpinRite was great. Spinrite stopped being any use sometime in the early 90s.

Re: Zxcvbn: realistic password strength estimation

#107

Earlier quoted context omitted.

It always bothers me a bit when I see analysis of password strength for compromised sites without any mention of the possibility that the account might just not be important to users. But there is a caveat. If the account is somehow identifiable as yours (say, because your friends know it's your account) then suddenly it's a possible social attack vector. Perhaps a weak one, but probably not something to be ignored,…

> It always bothers me a bit when I see analysis of password strength for compromised sites without any mention of the possibility that the account might just not be important to users. I actually use that as a factor when considering a password. If I think the site isn't going to be the most secure (a phpBB forum, or hand-rolled web-app), then I'm more likely to use a simple (but still relatively decent) password.

Recently I made a new password for some random site (and keep an encrypted record of it). Then I was relieved I did, because the site turned around and emailed the password right back to me. Unencrypted. In plaintext.

Hmm, that is wrong enough that I'll call them out by name... https://www.nbotickets.com/ (Is it polite and useful to email them how I feel about that? I feel like I'd just be "someone-is-wrong-on-the-internet"-ing. Advice?)

Re: Zxcvbn: realistic password strength estimation

#108
post #102
post #82

Earlier quoted context omitted.

I recently did a password change for some Apple site (iTunes, I think) and they handled this nicely. They put up a box beside the password field that listed the requirements, and as soon as I started typing it started dynamically changing the list to mark the requirements that my current entry did not meet.

I just went through the iTunes "forgot my password" process and had a different experience. According to that box to the side, my new password passed all their requirements, yet on submit it kept rejecting it. I finally got it to accept a password when I stopped trying to use spaces. Are there other characters their back end rejects that the front end allows?

Apple's entirely inconsistent in this: IIRC I've been able to set simple passwords if I reset my Apple ID password through a certain page, but am forced to use a complex password if I reset it through a different page. (Such as id.apple.com vs. store.apple.com vs. developer.apple.com) I can't remember which is which, but I remember coming to this realization multiple times.
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