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How we cracked millions of Ashley Madison passwords

cynosureprime.blogspot.com

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Re: How we cracked millions of Ashley Madison passwords

#41

Post by lostcolony »

jand wrote: post #34

For a non-native speaker, could you please confirm or invalidate my understanding of this interesting text: 1. They attacked some login/api-token unrelated to bcrypt. 2. If I use bcrypt-validate for logins and only temporarily associate rotating, random login/api-tokens with an account, I should not be prone to such attacks. Thank you very much for your help.

1. Yes 2. Yes

AM took the unencrypted password, lowercased it, and hashed it into an MD5 token that they then stored - conjecture is that it was used as a login token. That is what the article indicates was cracked, since MD5 is very weak, to get a lowercased password, then tried every permutation of capital letters on the bcrypted passwords, to get the actual passwords out.

To avoid similar issues, if you generate a token, don't use the unencrypted password as part of it. Random tokens are fine.

Re: How we cracked millions of Ashley Madison passwords

#42

Post by lostcolony »

nilved wrote: post #7

What's the risk of using plaintext passwords if we assume every user is employing long, random, unique passwords? This has always seemed like a non-issue to me because I've been using a password manager for a half-decade. e: Downvoting questions is mean. FWIW I always use bcrypt.

Let's also assume that any given server will never be hacked. It's more realistic.

Re: How we cracked millions of Ashley Madison passwords

#43

Post by KMag »

asadhaider wrote: post #6
chinathrow wrote: post #4

I abandon any sites which give me direct logins via URLs sent over plain text emails. I know, password reset keys are as bad as login keys, but usually they expire after a certain time frame. F*ck login keys.

Completely agree, Match.com does the same thing. Not so long ago a user signed up to their site using my email address (never figured out why). They were able to create an account and subscribe to the site without ever verifying the email, so for a week or so I was getting notifications sent to me without any way to unsubscribe from the email. Clicking any of the links in the email signed me in as the user and gave m…

> Not so long ago a user signed up to their site using my email address (never figured out why).

If they used legit billing information, with a name other than yours, it was probably a legitimate typo of the email address while signing up, using copy-paste to avoid typing the email address a second time. They probably haven't yet realized they aren't getting emails for their account.

Someone (or two people with the same name) has signed up for a Hertz car rental account and a trash removal service account using a name that could reasonably be mapped to my gmail username. I presume they either have @gmail.com or @.

Re: How we cracked millions of Ashley Madison passwords

#44

Post by dsp1234 »

I recently found out that piwik also uses a login token of the MD5 of the password[0]. So this mistake is still very prevalent.

If you want to provide a one-click automatic login to Piwik for your users, you can use the ‘logme’ mechanism, and pass their login & the md5 string of their password in the URL parameters:

https://stats.example.org/index.php?module=Login&action=logm...

[0] - http://piwik.org/faq/how-to/#faq_30

Re: How we cracked millions of Ashley Madison passwords

#45

Post by brusch64 »

valarauca1 wrote: post #9
nilved wrote: post #7

What's the risk of using plaintext passwords if we assume every user is employing long, random, unique passwords? This has always seemed like a non-issue to me because I've been using a password manager for a half-decade. e: Downvoting questions is mean. FWIW I always use bcrypt.

Could you recommend a good password manager?

I like KeePass and use it daily.

Re: How we cracked millions of Ashley Madison passwords

#46

Post by novaleaf »

ins0 wrote: post #5
flipp3r wrote: post #2

tl;dr they had a bad implementation and used md5 previously

they stored a static login key generated by md5(strtolower($username).'::'.strtolower($password)); - so they could crack the md5 part easly and bypass the bcrypt encryption

thanks for the writeup, that was the hunch from skimming the article but good to get confirmation!

Re: How we cracked millions of Ashley Madison passwords

#47

Post by jand »

lostcolony wrote: post #41
jand wrote: post #34

For a non-native speaker, could you please confirm or invalidate my understanding of this interesting text: 1. They attacked some login/api-token unrelated to bcrypt. 2. If I use bcrypt-validate for logins and only temporarily associate rotating, random login/api-tokens with an account, I should not be prone to such attacks. Thank you very much for your help.

1. Yes 2. Yes AM took the unencrypted password, lowercased it, and hashed it into an MD5 token that they then stored - conjecture is that it was used as a login token. That is what the article indicates was cracked, since MD5 is very weak, to get a lowercased password, then tried every permutation of capital letters on the bcrypted passwords, to get the actual passwords out. To avoid similar issues, if you generate a…

I cannot upvote yet, so: Thank you, I appreciate your help!

Re: How we cracked millions of Ashley Madison passwords

#48

Post by calgoo »

davidshepherd7 wrote: post #22
asadhaider wrote: post #6

Earlier quoted context omitted.

Completely agree, Match.com does the same thing. Not so long ago a user signed up to their site using my email address (never figured out why). They were able to create an account and subscribe to the site without ever verifying the email, so for a week or so I was getting notifications sent to me without any way to unsubscribe from the email. Clicking any of the links in the email signed me in as the user and gave m…

I had the same thing, but I was unable to even log in and stop the emails. I had to just mark it all as spam in the end.

I have a nice Volvo dealership in California that is sending me updates on someones car service, as well as the billing for some storage locker as well.

Apart from that, i get about 5 to 10 of real emails like this each month. Looking at the email addresses in Gmail i can see a lot of address that try to use a period in the address.

Re: How we cracked millions of Ashley Madison passwords

#49

Post by rakoo »

JosephRedfern wrote: post #25
sillysaurus3 wrote: post #19

Earlier quoted context omitted.

The login process looks like: User navigates to login screen and sends plaintext password to server. Server hashes the plaintext password and compares it to the hash on disk. If the hashes are equal, the server grants access. Since a user can only submit a plaintext password, not a hash, then they won't be able to log in unless they know the correct plaintext password. Even if they have a copy of the server's db, the…

I get that - but in a majority of cases, isn't "juicy" information going to be held in the DB anyway? Sure, you won't be able to go in through the "front door", but if you can get a copy of the password hash from a database dump is it not pretty much game-over anyway? If you're able to perform SQL injection against the DB, would you not be able to change the password in order to gain access to the system, or grant ad…

It depends what you're after. If you see that someone is subscribed to Ashley Madison and what to blackmail him/her, then you have what you need. On the other hand, the password is the most important thing, because the majority of people use the same password everywhere; if you have the password from AM, maybe you have the one for GMail or for the bank account, where the real "juice" is at.

Re: How we cracked millions of Ashley Madison passwords

#50

Post by steckerbrett »

stephenr wrote: post #26
nilved wrote: post #7

What's the risk of using plaintext passwords if we assume every user is employing long, random, unique passwords? This has always seemed like a non-issue to me because I've been using a password manager for a half-decade. e: Downvoting questions is mean. FWIW I always use bcrypt.

If I breach your environment and get access to bcrypt hashes, they are useless to me as-is. If I have enough processing power to brute-force compare them, I can eventually get the original password back, but that isn't a zero-cost effort in terms of time. As soon as you realise you have been breached, I would expect you would have initiated a lockdown of some kind, either preventing access to accounts until the owner…

If you have the computing power? If you're compromising peoples boxes you likely also have a botnet, which has practically limitless potential.
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