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Blizzard Network Breached; Change Your Battle.Net Passwords

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Re: Blizzard Network Breached; Change Your Battle.Net Passwords

#121

Post by cryptbe »

zaroth wrote: post #94

SRP is great at many things, but terrible at securing the server-side password database from brute force attacks. A quick look at http://srp.stanford.edu/design.html and http://srp.stanford.edu/demo/demo.html and you can see that SRP uses simple SHA1 plus a Salt to store the hashed passwords. With the hashes and salts stolen, please assume your password has been brute forced by the attacker (1 billion hashes per seco…

It seems like you either didn't actually read the RFC or read but didn't understand, then made a fuss out of your ignorance.

SRP uses SHA1, but not just that. Here is the relevant part of the RFC [1]:

The host stores user passwords as triplets of the form

        { , ,  }

   Password entries are generated as follows:

         = random()
        x = SHA( | SHA( | ":" | ))
         = v = g^x % N*
[1] http://www.ietf.org/rfc/rfc2945.txt

Re: Blizzard Network Breached; Change Your Battle.Net Passwords

#122

Post by tedunangst »

zaroth wrote: post #114
thechut wrote: post #99

Earlier quoted context omitted.

SRP is supposed to make use of multiple types of entropy to ensure the passwords are far more complicated that salted SHA1. While I agree it's possible that the attackers also got this information but I don't think we can jump to conclusions about the overall security of the passwords until more information is known.

Please read the RFC, it's right here: http://www.ietf.org/rfc/rfc2945.txt Password entries are generated as follows: = random() x = SHA( | SHA( | ":" | )) = v = g^x % N G = 47 N = 112624315653284427036559548610503669920632123929604336254260115573677366691719 What was stolen was no better than LinkedIn hashes -- for the purposes of dictionary attacking the database

g^x is slow, therefore better than linkedin hashes for the purpose of dictionary attacking the database.

Re: Blizzard Network Breached; Change Your Battle.Net Passwords

#123

Post by tedunangst »

zaroth wrote: post #115
mindslight wrote: post #112

Earlier quoted context omitted.

I haven't studied SRP, but a quick look at it and it seems that one also needs to perform the v = g^x. While still vulnerable to brute forcing due to lack of entropy in a password, this is more expensive than bare SHA1. The opine.me post you linked elsewhere completely glosses this over. edit: okay, just to give you some very rough numbers from 'openssl speed' on my machine. 16 byte SHA1 is about 1M/sec. Projected ds…

See below, the algorithm is clearly specified in the RFC, and it's no better than plain SHA1 in terms of preventing dictionary attacks once the database is stolen.

Whatever logic you are using to prove that performing g^x is the same as computing plain sha1 would also prove that bcrypt and pbkdf2 are no better than sha1.

Re: Blizzard Network Breached; Change Your Battle.Net Passwords

#124

Post by zaroth »

cryptbe wrote: post #121
zaroth wrote: post #94

SRP is great at many things, but terrible at securing the server-side password database from brute force attacks. A quick look at http://srp.stanford.edu/design.html and http://srp.stanford.edu/demo/demo.html and you can see that SRP uses simple SHA1 plus a Salt to store the hashed passwords. With the hashes and salts stolen, please assume your password has been brute forced by the attacker (1 billion hashes per seco…

It seems like you either didn't actually read the RFC or read but didn't understand, then made a fuss out of your ignorance. SRP uses SHA1, but not just that. Here is the relevant part of the RFC [1]: The host stores user passwords as triplets of the form { , , } Password entries are generated as follows: = random() x = SHA( | SHA( | ":" | )) = v = g^x % N* [1] http://www.ietf.org/rfc/rfc2945.txt

cryptbe - I quoted the exact same text from the RFC in a post below. Sheesh...

From this it should be obvious to you that what SRP is doing is no better than SHA1 for protecting against dictionary attacks.

'g' and 'N' are well known numbers (also posted below). Username, and salt are known.

It's the perfect setup for high speed dictionary attacks. Please edit or delete your post. You can read my more lengthy post on this here: http://www.opine.me/blizzards-battle-net-hack/

Re: Blizzard Network Breached; Change Your Battle.Net Passwords

#125

Post by Splines »

RKearney wrote: post #20
swang wrote: post #4

"Some data was illegally accessed, including a list of email addresses for global Battle.net users, outside of China. For players on North American servers (which generally includes players from North America, Latin America, Australia, New Zealand, and Southeast Asia) the answer to the personal security question, and information relating to Mobile and Dial-In Authenticators were also accessed. Based on what we curren…

I believe Blizzard makes you supply a scanned copy of your state issued identification in order to get a password reset.

This sort of thing kind of bothers me. Is Blizzard in the business of verifying state-issued identification? What prevents me from photoshopping my target's name on top of my own ID?

Re: Blizzard Network Breached; Change Your Battle.Net Passwords

#127

Post by tedunangst »

david_shaw wrote: post #57
barik wrote: post #34

Earlier quoted context omitted.

The 16-character limit is not as bothersome to me as the fact that they go out of their way to set onpaste="false" in their HTML, making even 16-character passwords annoying because the average user has to type it all in by hand. I will never understand the rationale for preventing me from pasting a strong password versus picking a weaker password that I have to type by hand. Currently, my workaround is to use "Inspe…

Rather than doing this by hand via Firebug/Chrome Inspect Element, it might be worth looking into creating a quick Chrome Extension or Firefox Add-On (or even a userscript) to do this for you. I understand the initial rationale behind not allowing you to paste a password: (1) Pasting a password can allow a malicious user to find your password somewhere and paste it in (as it would take much more time to type by hand)…

(3) you type your intended password wrong, copy it, paste it, and lock yourself out. The sites make you type the password twice is to make sure you did it right. People who can't be bothered to type a password twice are probably heavily intersecting with people who didn't type it right the first time.

Re: Blizzard Network Breached; Change Your Battle.Net Passwords

#128

Post by zaroth »

zaroth wrote: post #114
thechut wrote: post #99

Earlier quoted context omitted.

SRP is supposed to make use of multiple types of entropy to ensure the passwords are far more complicated that salted SHA1. While I agree it's possible that the attackers also got this information but I don't think we can jump to conclusions about the overall security of the passwords until more information is known.

Please read the RFC, it's right here: http://www.ietf.org/rfc/rfc2945.txt Password entries are generated as follows: = random() x = SHA( | SHA( | ":" | )) = v = g^x % N G = 47 N = 112624315653284427036559548610503669920632123929604336254260115573677366691719 What was stolen was no better than LinkedIn hashes -- for the purposes of dictionary attacking the database

Define slow tedunangst - Big O notation please.

Maybe you can look here: http://en.wikipedia.org/wiki/Modular_exponentiation.

Ok, I'll save you the trouble -- the modular exponentiation is O(log exponent). That's log as in... FAST.

Re: Blizzard Network Breached; Change Your Battle.Net Passwords

#129

Post by zaroth »

tedunangst wrote: post #123
zaroth wrote: post #115

Earlier quoted context omitted.

See below, the algorithm is clearly specified in the RFC, and it's no better than plain SHA1 in terms of preventing dictionary attacks once the database is stolen.

Whatever logic you are using to prove that performing g^x is the same as computing plain sha1 would also prove that bcrypt and pbkdf2 are no better than sha1.

v = g^x % N

Finding 'x' given g, v, and N is HARD. Calculating g^x is EASY. O(log X)

This is crypto 101 man...

This is why SRP is said to be verifier based and not password or password-equivalent based, because you cannot retrieve X from v.

But this is ALSO why the CREATOR of SRP Thomas Wu specifically states in his presentations on SRP that it does not resist dictionary attacks when the verifier database is stolen.

Re: Blizzard Network Breached; Change Your Battle.Net Passwords

#130

Post by StevenRayOrr »

Auguste wrote: post #89

How can I change my security questions? I can't find them in the account settings.

As far as I can tell, you can't. But Blizzard has announced that they will be putting something in place for users to do that in the next few days. Keep an eye on your B.Net email.
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