Battle.net authentication misconceptions

http://www.skullsecurity.org/blog/2012/battle-net-authentication-misconceptions

by icehawk • 14 years ago

60 36 14 years ago

tzaman• 14 years ago

Hopefully this lay some of the paranoid guys to rest.

Auguste• 14 years ago

It's alright to be paranoid, but most of the security-related posts on the Diablo 3 forums I've seen have been pure FUD.

VikingCoder• 14 years ago

"Yes, the passwords are converted to uppercase before hashing. That's probably a bad idea - especially in the modern world - but it really dates back to their first Battle.net game - Diablo - from 1996."

Yup, that's probably a bad idea. Thank goodness you didn't disagree that it's probably a bad idea, like I've seen a ton of nut-jobs do.

That said, I think it's only "probably a bad idea" in terms of protecting people who use the same password on multiple sites, which is "without question a bad idea."

davis_m• 14 years ago

Why is it worse to uppercase the password before hashing for people who use the same password on multiple sites? It doesn't matter if it is a 24 character password using every character set possible, if it is the same password they use somewhere else, and that place is compromised, the attacker will be able to use that password to login to the Battle.net account.

lawnchair_larry• 14 years ago

The reason is because lowering the entropy of the password makes the blizzard version easier to crack. If blizzard is compromised, the passwords won't be disclosed - just the hashes will be, so re-use isn't immediately an issue. It becomes an issue when the hash is cracked and the attacker can now see which password is being reused, and then reuse it. Of course if the reused password is something like "hunter2", the cracked version will look like "HUNTER2", but the original case can be guessed in a few tries once the case-insensitive version is discovered.

Very roughly, case sensitivity provides about a half bit of entropy. For reference, one bit of entropy takes twice as long to crack.

And say what you want about password reuse, but 99% of users re-use passwords at least somewhat, so site owners have an obligation to protect user passwords.

lnanek• 14 years ago

Put me in as a nut job then. I've seen plenty of users who make no distinction whatsoever re case of characters in passwords. One day their password is working, the next day it isn't, and the organization ends up spending the custom care money to deal with it just because they started typing "af" at the end of their password instead of "Af" or whatever.

If you need more complexity in a password, better to just encourage them to use a phrase with the words being the individual complexity rather than the characters. Like it or not, we live in a world where 80% of end users can't turn their wifi radio on and off on their phone, and we need to make systems that are a pleasure to use for them.

TillE2• 14 years ago

Condescension about idiot users is never a very persuasive way to make a point.

> we live in a world where 80% of end users can't turn their wifi radio on and off on their phone

But they still manage to properly enter their case-sensitive password to buy new apps.

TillE2• 14 years ago

Er, wow. That's horrendous. How in the world can they still blame the first Diablo when they made such a big deal about "Battle.net 2.0" recently? Why do they need to lump the new stuff together with legacy systems using broken security practices?

cube13• 14 years ago

Most likely because the authentication codebase started with Starcraft, was integrated with Diablo 2, then was basically ported to WoW.

After that, WoW's system was basically integrated into the current Battle.net 2.0 system.

nmb• 14 years ago

Seems to be a spreading practice for services with huge userbases; Facebook does it: http://www.zdnet.com/blog/facebook/facebook-passwords-are-no...

biafra• 14 years ago

facebook does a different thing. It does not allow any casing(sp?). It allows only the right and the reverse and first letter in uppercase.

Blizzard seems to uppercase the given password and hashes that. This method makes a lot of wrong passwords work. In facebooks case only two more passwords than the original are accepted.

ianburrell• 14 years ago

Facebook does something different. They accept two extra variants of the password (first letter capitalized and case reversed). They don't uppercase the password before hashing or checking. This reduces the security slightly as opposed to uppercasing passwords which reduces the search space significantly.

jsabo• 14 years ago

If they ever compromise the bnet database of hashed passwords though it may be a benefit, as the password they re-use may contain uppercase and lowercase letters, which the bnet database has no way of representing.

nknight• 14 years ago

He's actually wrong. Starcraft introduced usernames/passwords and unique names to Battle.net in early 1998. The support was then patched into Diablo 1.05. Diablo I's Battle.net functionality did not originally include usernames/passwords at all.

It was quite a strange little architecture, initially. Your displayed name was whatever you'd named your character, with the distinguishing feature being an "account number" that could be re-generated by deleting a file in your Diablo directory (the corollary being if you didn't back the file up, your account number would change upon a reformat or migration to a new computer).

ohashi• 14 years ago

Or you used a tool to change your account to 1537 and nobody could ever find you because hundreds, if not thousands, of people all used that same shared account.

timewasted• 14 years ago

Ultra minor nit-pick, but your account number was stored in a registry entry (HKEY_LOCAL_MACHINE\SOFTWARE\Battle.net\Configuration), not a file.

The account number consisted of four parts:

  Registration Version: This was always 1 for all the account numbers that I still have lying around.
  Registration Authority: I don't actually remember what this was used for.
  Client ID: The actual account number.
  Client Token: Random number used to verify the validity of the Client ID.

Confusion• 14 years ago

If the passwords are stored using proper key stretching techniques and salting, they don't need to have much entropy to withstand brute-forcing. It's not necessarily a problem that lowercase letters do not contribute. However, it is a completely unnecessary lowering of entropy.

My lesson from this is: it always pays to think about and understand even the seemingly most trivial decision. You may be stuck with it for decades.

bicknergseng• 14 years ago

Warning: somewhat unrelated and probably a rant:

Can I just say that Blizzard's handling of the Diablo 3 launch was a travesty on so many levels? First of all, nothing worked. No one could login to play, despite their stress testing beta and having a large percentage of players sign up and predownload far before launch. Their response was the now internet famous "Error 37," an absolutely useless message for users. If everything was going to be completely broken, they could have at least provided a useful error message saying "We're getting more traffic than anticipated and will notify you when the servers are ready." or something.

Seriously one of the most disappointing end user experiences I have ever had, and there's no way for me to return my $60 download.

rmassie• 14 years ago

It was one day. Get over it. The game has worked very well since.

ubercore• 14 years ago

Not totally well. I still get lag spikes in a _single player game_. It's really confusing to me why they make the client rely on the server, especially when I've turned off "quick join" mode.

ender7• 14 years ago

Really? Your is a common complaint, so perhaps I'm just weird, but I was neither surprised nor upset by the opening day crunch. It was certainly nothing compared to, for example, WoW's release day. Or some of Steam's releases, back in the day.

With D3, I logged in on release day, got the error a few times. Came back a couple hours later, and managed to log in. Played around a bit, had a good time. There were some occasional lag spikes, but nothing catastrophic. The next day, I had no problems with logging in at all (only a very occasional lag spike). All days since have been smooth sailing.

ralfd• 14 years ago

I don't get what the problem is? It doesn't really make bruteforcing an account feasible, that there are only a lower Quadrillion number of combinations instead of Quintillion.

Quote:

> If you fail a certain number of logins against Battle.net, your IP address is temporarily banned. This makes it fairly difficult to bruteforce most accounts.

alexrp• 14 years ago

I'm just going to interject here: http://xtzgzorex.wordpress.com/2012/05/26/grunt-auth-misconc...

Battle.net authentication misconceptions

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