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Yahoo discloses hack of 1B accounts

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Re: Yahoo discloses hack of 1B accounts

#91

Post by agf »

ubercore wrote: post #79
alyandon wrote: post #11

"Separately, we previously disclosed that our outside forensic experts were investigating the creation of forged cookies that could allow an intruder to access users’ accounts without a password. Based on the ongoing investigation, we believe an unauthorized third party accessed our proprietary code to learn how to forge cookies." So that exactly explains how my Yahoo account was used to send spam despite having a pa…

What do you mean by a password that can't be reasonably brute forced? EDIT: To clarify, I mean specifically with md5. I'm by no means an expert, just curious because I had considered md5 so broken that this comment caught my attention.

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.

Re: Yahoo discloses hack of 1B accounts

#92

Post by inopinatus »

ponco wrote: post #28

I almost hope the data is made somewhat public so Troy / https://haveibeenpwned.com/ can get a hold of it and provide the public with reassurance.

By now I suspect you can simplify it down to just matching on the RHS for any domain registered to Yahoo.

Re: Yahoo discloses hack of 1B accounts

#93

Post by Alex3917 »

camus2 wrote: post #36
xanadohnt wrote: post #29

Earlier quoted context omitted.

Web tokens, for example, don't necessarily include just a session ID. Some include the full session details within its payload. This can be quite useful, actually, because it offloads session-lookup onto the client.

How do you invalidate a JWT server-side without the user interacting with the server ?

Each JWT has an issued at date, so you just need to reject all tokens issued before that time. In addition to invalidating all tokens if there is a breach, each user account can have its own datefield to invalidate all the tokens for that account if a user changes their password or whatever.

Re: Yahoo discloses hack of 1B accounts

#94

Post by metafunctor »

ubercore wrote: post #79
alyandon wrote: post #11

"Separately, we previously disclosed that our outside forensic experts were investigating the creation of forged cookies that could allow an intruder to access users’ accounts without a password. Based on the ongoing investigation, we believe an unauthorized third party accessed our proprietary code to learn how to forge cookies." So that exactly explains how my Yahoo account was used to send spam despite having a pa…

What do you mean by a password that can't be reasonably brute forced? EDIT: To clarify, I mean specifically with md5. I'm by no means an expert, just curious because I had considered md5 so broken that this comment caught my attention.

A preimage attack for MD5 has complexity of about 2^123. So, even if you get the MD5 hash for a password, it will be exceedingly hard to find a password that has the same hash (assuming the original password is long and random).

Re: Yahoo discloses hack of 1B accounts

#95

Post by yuhong »

pluma wrote: post #83
scrollaway wrote: post #13

Earlier quoted context omitted.

It's really not. Unsalted MD5 has been shameful for a long, long time.

As a data point: when I was a teenage code monkey in 2004 writing PHP I already understood that unsalted MD5 is unsafe. According to Wikipedia: * 2004 it became possible to find MD5 collisions at a rate of one per hour on a cluster * 2005 it became possible to do this within "a few hours" on a consumer laptop * 2006 it became possible to do this within one minute * nowadays it's possible to do this "within seconds" P…

MD5 collisions are probably not important for passwords.

Re: Yahoo discloses hack of 1B accounts

#97

Post by [deleted] »

ubercore wrote: post #79
alyandon wrote: post #11

"Separately, we previously disclosed that our outside forensic experts were investigating the creation of forged cookies that could allow an intruder to access users’ accounts without a password. Based on the ongoing investigation, we believe an unauthorized third party accessed our proprietary code to learn how to forge cookies." So that exactly explains how my Yahoo account was used to send spam despite having a pa…

What do you mean by a password that can't be reasonably brute forced? EDIT: To clarify, I mean specifically with md5. I'm by no means an expert, just curious because I had considered md5 so broken that this comment caught my attention.

[deleted]

Re: Yahoo discloses hack of 1B accounts

#98

Post by haser_au »

x0 wrote: post #75
dopamean wrote: post #56

Earlier quoted context omitted.

I'm genuinely curious how the decision to use MD5 gets made. Who says, "hey, maybe we should use MD5." And then who responds, "that sounds like a great idea Bob." Seriously. I've known for years that MD5 is insufficient for hashing passwords and I'm just some random guy. This kind of thing really baffles me.

And nobody ever seemed to say "hey, maybe we should be using something more secure". Yahoo's been around for how many decades, and the fact they were still using MD5 in 2013 is just shameful. Yeah if it was some legacy code from 1993 you can probably excuse it, but I just can't believe after 20 years nobody thought it was a problem. I'm not really a software developer but I really can't imagine it being a huge change…

There are likely to be a lot of identity systems using the password in the database, all of which have been coded to look for an MD5 hash, not a salted hash. This means code in a number of applications have to be updated at the same time.

The typical way around this is to create your new destination column (e.g. sha256 with salt), and progressively have applications reference this column rather than the MD5 unsalted column.

It's a huge amount of work, and if the applications were made in 1990's, the code is likely legacy. If Yahoo are doing regular code security reviews, this will likely have been put in the pile of "we need to fix, but it's too costly to do".

Re: Yahoo discloses hack of 1B accounts

#99

Post by cm2187 »

mkhpalm wrote: post #30

Guys... let's just delete our Yahoo accounts. That company can't go bankrupt fast enough. It will sell our data for quarters.

But I'm afraid I have no sympathy for outraged users. No more than if it was gmail or hotmail. They didn't pay for the service, they got an email service for free. It's hard to complain when it is free. And they did enter into an agreement where they sell their privacy against a free service.

Re: Yahoo discloses hack of 1B accounts

#100

Post by aidenn0 »

noxToken wrote: post #68
mkhpalm wrote: post #30

Guys... let's just delete our Yahoo accounts. That company can't go bankrupt fast enough. It will sell our data for quarters.

You're right, but it goes beyond that. Yahoo used to be a titan. I was a regular user of Yahooligans back in the day. Yahoo (at one time) had been my go to search engine. I can't say that it was ever my primary email account, but I used it. I used Yahoo Messenger. I was part of a community that centered around some Yahoo games. Yahoo used to be a titan that was a direct Google competitor in the realms of communicatio…

Yahoo was my primary (as in only one not provided by my isp or school) e-mail address from when they bought Geocities until the early '00s. I've been disentangling as many services from them as possible over the past couple of years.
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