Yahoo discloses hack of 1B accounts • Hacker News Board

Re: Yahoo discloses hack of 1B accounts

#341

Post by Frondo » Thu, Dec 15, 2016, 2:17 AM UTC

ausjke wrote: post #24

I'm speechless. More and more are migrating to cloud these days, I expect more and more epidemic leakage will come. I host everything myself except for email, which is always a headache but contains more private info than all others I manage combined. Maybe it is time to run a small email server again but it is easily said than done, gosh please give me something like a working PGP or whatever for safe emails(PGP is…

I've heard that setting up an outbound email server on places like Linode or DO is tricky, because of how likely it is the IP block you're on will be considered spammy. To get around that, I rent a VPS from a local ISP here in Seattle. They have their own equipment, their own IP ranges, etc. It's a bit spendier than Linode but it's not breaking the bank.

Re: Yahoo discloses hack of 1B accounts

#342

Post by danielweber » Thu, Dec 15, 2016, 2:20 AM UTC

pbhjpbhj wrote: post #269

Endy wrote: post #123

Earlier quoted context omitted.

From everything I've read, the engineers did. The problem was that the security team had to go head-to-head with the budget team. And unfortunately, the budget team won - since the upper levels didn't feel that the IT security salaries were a necessary expenditure. And beyond that, there was concern that making people actually change their passwords regularly and requiring anything like security in said passwords was…

> The problem was that the security team had to go head-to-head with the budget team. // Wouldn't engineers at such a big corp whistle-blow such incompetent decision making? Apparently [1] they had a $1.37B net income in 2013. Given using bcrypt with a Blowfish hash and salting was pretty much a de facto standard by that point (I think that's what Wordpress were doing, hardly revolutionary security work) it seems the…

It's not that hard to implement something at the start. It's more work to retrofit it on top of an existing system in a way that doesn't reduce the total security.

Re: Yahoo discloses hack of 1B accounts

#343

Post by danielweber » Thu, Dec 15, 2016, 2:21 AM UTC

lotyrin wrote: post #194

cm2187 wrote: post #141

Earlier quoted context omitted.

But would it require users to change their password? The way I would have implemented it, but would be keen to know how secure it is, is that you start with the md5 of the password ( md5(password) ). You then bcrypt or scrypt that md5 ( bcrypt(md5(password)) ) and replace the md5 in your database with the bcrypt hash. When a user logs in, all you need to do is to calculate the md5 first then check that md5 against th…

The method I've used is to add the column for the new stronghash then you update the old column to stronghash( ), where is dumbhash(password) check against that on login stronghash(dumbhash(password)) and generate just stronghash( ) while you have the plaintext password in memory and update the row to add the new hash (simple and interoperable, not dependent on dumbhash) and drop the stronghash( ). After a limit (to…

This is fine workflow, but keep in mind

> and do a "we sent you a reset email" for anyone that's trying to log in but has no password hash.

Yahoo is an email provider so many of these users won't have an external provider to refer to.

Re: Yahoo discloses hack of 1B accounts

#344

Post by b2600 » Thu, Dec 15, 2016, 2:22 AM UTC

curiousDog wrote: post #289

sqldba wrote: post #230

Technically; no. Bureacratically; maybe. Given the skill and self direction of offshore workers; impossibly.

While some offshore workers might not be MIT grads (/s) like you, branding them all as an incompetent group is neither fair nor correct. If offshoring didn't provide tangible value to the US IT industry it would've been shut down a while ago.

The tangible benefit is working for less money.

Re: Yahoo discloses hack of 1B accounts

#345

Post by dmckeon » Thu, Dec 15, 2016, 2:22 AM UTC

Arubis wrote: post #165

Fittingly, attempting to change my password to a 32-character random string generated by 1Password returns an error that the password "cannot contain my email or username", regardless of the contents of that random string (I tried several). It does, however, _happily_ accept `passwordpassword` and cheerily move along to confirming that my recovery email account from 2003 is still valid.

I hit this on the last Yahoo hack go-round, and it seemed that having a name in the form 'F Lastname' (for example) disallowed use of the letter F in the password.

I say "seemed" as I did not go through the exercise of testing with multiple combinations of name, initial, and password.

Re: Yahoo discloses hack of 1B accounts

#346

Post by jsjohnst » Thu, Dec 15, 2016, 2:22 AM UTC

manarth wrote: post #170

agf wrote: post #91

Earlier quoted context omitted.

If it's a password so long and complex it wouldn't be in any rainbow table computable in reasonable time. While MD5 can be computed quickly, there is still a limit to how many you can compute -- and there are an infinite number of possible passwords if they aren't length limited.

Rainbow tables are attacks against secure algorithms. MD5 is recognised as an insecure algorithm: given a known hash, there are multiple possible passwords that would resolve to the same hash, therefore appearing to be the correct password. With MD5, it's not necessary to compute an infinite number of possible passwords, and it is possible that, given a particular hash, a collision can be found within a reasonable ti…

Either a) you don't have a clue about the complexity involved in finding a collision for a specific hash or b) your definition of "reasonable time" is longer than the age of the universe and/or using 100 trillion state of the art GPUs is realistic.

I'm leaning towards option a, you read a blog post once and think you're an expert on cryptography now.

Re: Yahoo discloses hack of 1B accounts

#347

Post by dlubarov » Thu, Dec 15, 2016, 2:23 AM UTC

sk5t wrote: post #319

AsyncAwait wrote: post #310

Earlier quoted context omitted.

if the password is stored properly, (i.e. bcrypt), the number of characters shouldn't matter at all, be it 50 or 5000.

It sort of does matter for bcrypt, surprisingly: http://security.stackexchange.com/questions/39849/does-bcryp... In the interests of hewing closest to cryptographic reality, I design not to allow a password longer than the algorithm can usefully use.

I think it's best to allow longer passwords for those who use long phrases. It's easier to remember the full phrase than a truncated version. You could show a warning that the extra chars beyond 50-55 will be ignored.

Re: Yahoo discloses hack of 1B accounts

#348

Post by schoen » Thu, Dec 15, 2016, 2:23 AM UTC

cm2187 wrote: post #282

jsjohnst wrote: post #267

Earlier quoted context omitted.

I've done it before on a 1 billion word / password list and didn't get any collisions.

That being said md5 does generate collisions. I was playing with the IMDB movie database that you can download. They use a combination of the title and the year as a primary key. I tried using an md5 instead to save space (but giving a reproducible ID instead if an identity column), and got many collisions. No collision with SHA256.

Wait, what? No MD5 collisions at all were publicly known until Xiaoyun Wang disclosed one in 2004 using a new cryptographic technique she invented (explained in Wang and Yu's "How to Break MD5 and Other Hash Functions").

MD5 has a 128-bit output so collisions that occur by chance should require about 2⁶⁴ inputs (18 exa-inputs). Surely your database didn't contain over 2⁶⁴ different movie records.

Could you take a look at what you were doing again? Your description doesn't really make sense mathematically.

Re: Yahoo discloses hack of 1B accounts

#349

Post by b2600 » Thu, Dec 15, 2016, 2:23 AM UTC

cookiecaper wrote: post #330

throwaway1X2 wrote: post #262

Earlier quoted context omitted.

Yes, 'offshore' is a race. Every critique is a racism. Coming from said 'offshore' (at least in regards to the US), I see that 'quality' people work remotely for monies comparable to the onsite workers, launch startups, et cetera. If you outsource to the offshore for the costs, guess what, you get lesser quality for the said cost. Nothing racist in that, but I understand your position - a SJW to every household!

Yes. We pay an independent Indian contractor rates that are fully competitive with any American contractor's rates. If someone has the same skillset as the competition, their rate is going be in the same ballpark, no matter where they live.

If your statement is accurate, why offshore the work?

Re: Yahoo discloses hack of 1B accounts

#350

Post by danielweber » Thu, Dec 15, 2016, 2:24 AM UTC

cm2187 wrote: post #282

jsjohnst wrote: post #267

Earlier quoted context omitted.

I've done it before on a 1 billion word / password list and didn't get any collisions.

That being said md5 does generate collisions. I was playing with the IMDB movie database that you can download. They use a combination of the title and the year as a primary key. I tried using an md5 instead to save space (but giving a reproducible ID instead if an identity column), and got many collisions. No collision with SHA256.

You likely goofed something up. No one has demonstrated two strings that are conceivably used as passwords that users type in -- and that includes the tuple {movie title:year} -- that have MD5 collisions.

The security problem with MD5 isn't collisions.