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Evernote hacked

blog.evernote.com

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Re: Evernote hacked

#141

Post by pbhjpbhj »

djhworld wrote: post #85
UnoriginalGuy wrote: post #11

The following blog post is also being sent to all Evernote users as an email communication. Evernote’s Operations & Security team has discovered and blocked suspicious activity on the Evernote network that appears to have been a coordinated attempt to access secure areas of the Evernote Service. As a precaution to protect your data, we have decided to implement a password reset. Please read below for details and inst…

I never received this email. I only found out about the hack because my evernote client kept on bugging me saying my password had changed. Curious as to why I found out the cause via Twitter. Email is way too slow for these sorts of things

Me neither - I wonder if in fact Evernote's website was hacked instead ...

Re: Evernote hacked

#142

Post by Niten »

catharsis wrote: post #133
Niten wrote: post #122

Earlier quoted context omitted.

Anyone using this comic to imply that a passphrase is more secure than a short random password hasn't done the math. This is comparing a passphrase drawn from four of the 2048 most common words against not a random password, but one based on a mutated version of one of the 65536 most common words. The example passphrase does have the equivalent of 44 bits of entropy: log_2 (2048^4) = 4 * 11 = 44 However, if we take a…

This assumes that it is known that the password is four random words. The security of this method hinges on the fact that that information is not known.

That's not the case, though. Even knowing the general manner in which the passphrase is constructed, if the four words are randomly selected then the best an attacker can do is to brute force the space of 2^44 possible phrases, which is difficult enough to be considered secure. The very same can be said for the seven-character random password: the best an attacker can do, knowing how the password is constructed, is to brute-force a space of about 2^46 possible passwords, which is secure enough.

And this must be true in order for passphrases to be a reasonable choice. Because if people start using passphrases commonly, then this formulation will immediately be added to password cracking toolchains along with all the other common types of password.

On the other hand, the passphrases's actual "entropy" is probably lower than the advertised 44 bits, because patterns like the appearance of an adjective ("correct") before a noun ("horse") are common enough in the English language that they, too, could be factored into a smart password cracking tool.

Re: Evernote hacked

#143

Post by landhar »

UnoriginalGuy wrote: post #11

The following blog post is also being sent to all Evernote users as an email communication. Evernote’s Operations & Security team has discovered and blocked suspicious activity on the Evernote network that appears to have been a coordinated attempt to access secure areas of the Evernote Service. As a precaution to protect your data, we have decided to implement a password reset. Please read below for details and inst…

> Even though this information was accessed, the passwords stored by Evernote are protected by one-way encryption. (In technical terms, they are hashed and salted.

Were the attackers ables to access the salt ?

Re: Evernote hacked

#144

Post by santiagoIT »

I got the email and reset my password (web browser on desktop). I then launched the MaxOs client app and it asked me to enter the new password, however the iOS app shows its initial loading screen but then just crashes. It never gets around to asking me for the new password. Anyone know a solution to this?

Re: Evernote hacked

#145

Post by Terretta »

Niten wrote: post #122
Terretta wrote: post #109

Earlier quoted context omitted.

Your blog post says: > "Avoid using simple passwords based on dictionary words" And yet your password algorithm rejects highly secure pass phrases: > "New passwords can contain letters, numbers and punctuation." Disallowing spaces is particularly annoying for a company with a strong security requirement, as passphrases are simultaneously far more secure and far more memorable than the monkey rules your validation dem…

Anyone using this comic to imply that a passphrase is more secure than a short random password hasn't done the math. This is comparing a passphrase drawn from four of the 2048 most common words against not a random password, but one based on a mutated version of one of the 65536 most common words. The example passphrase does have the equivalent of 44 bits of entropy: log_2 (2048^4) = 4 * 11 = 44 However, if we take a…

> to imply that a passphrase is more secure than a short random password

I noted to internalize the idea, the entropy idea versus human "random" passwords which aren't random at all. "Normals" are using their name with a 3 instead of an E, or some word with a 1 on the end. This tends to put them in rainbow tables or easy attacks. See my link #1 in GP comment for reference.

That's why I said "pass-phrases are stronger than monkey rules".

Meanwhile, "random" passwords don't necessarily come up stronger. Forget just seven. Let's use 1Password's random sixteen (16) char generator as an example[1]:

    2Fro%7gMfQbwBktm : 85.3 bits of entropy from 72 char set
    [xNyCHZc44RzPeMJ : 85.1 bits of entropy from 82 char set
Meanwhile, going by length and charset alone and ignoring whether the characters are words (using my passphrase from GP comment):

    thisphraseisdefinitelynotinthedictionary : 153.7 bits of entropy from 26 char set
The thing is, when you're attacking Evernote's database, you don't know someone's using XKCD's idea. So you're not looking at (2048^4) [2]. You're looking at (using the XKCD password):

    correct horse battery staple : 104.2 bits from 27 char set
If as an attacker we magically know "thisphraseisdefinitelynotinthedictionary" is words without spaces, and even assume they come from the 2048 word set (though neither "definitely" nor "dictionary" are in that 2048 word set), then by your formula:

    log_2 (2048^8) = 8 * 11 = 88 bits of entropy
markedly stronger than your example random password's 45.99 bits. And as I noted, "far more memorable", meaning such a phrase could be used by regular folks.

1. Quick entropy check: http://rumkin.com/tools/password/passchk.php

2. Manual entropy check: http://www.wolframalpha.com/input/?i=log_2%282048%5E4%29

Re: Evernote hacked

#146

Post by uptown »

lysium wrote: post #98

I'm wondering how they perform the password reset. Surely, you must know more than the username. But they cannot rely on the old password either, because the whole thing was set off by assuming that the old password is hacked. And they advise their user to ignore instructions per email. So how do / could they do it?

It contradicts their instructions, but I'm assuming using the password-reset received email immediately following my request for this email is the "right" way to do this. I believe the intent of what they warned against were common phishing emails .

Re: Evernote hacked

#147

Post by maxcan »

tomjen3 wrote: post #37
UnoriginalGuy wrote: post #11

The following blog post is also being sent to all Evernote users as an email communication. Evernote’s Operations & Security team has discovered and blocked suspicious activity on the Evernote network that appears to have been a coordinated attempt to access secure areas of the Evernote Service. As a precaution to protect your data, we have decided to implement a password reset. Please read below for details and inst…

I haven't received such an email, wonder why. Anyway Evernotes android client wasn't very good and it was far too slow to start. And now the have been hacked. Anybody know a good alternative?

I've heard good things about pocket

Re: Evernote hacked

#148

Post by Niten »

miles wrote: post #137
catharsis wrote: post #133

Earlier quoted context omitted.

This assumes that it is known that the password is four random words. The security of this method hinges on the fact that that information is not known.

Exactly. In a thread about "900gage!@#" being cracked in a few hours[1], this same discussion came up. It's worth reading for those who are wondering about passphrases vs. complex passwords. [1] http://news.ycombinator.com/item?id=4545893

This is, again, not about a random password, as moxie explains in that thread. And as he continues, with regard to the comic: "I think that's totally on the right track, but if people start to do that, chances are that they'll start to create exploitable patterns again".

Any password cracker smart enough to exploit the patterns in "900gage!@#" is also smart enough to exploit the construction of an English language passphrase. The passphrase is still secure enough (probably), but it is not more secure than the random password. And if there is any one thing to take away from that thread, it should be that it's foolish to assume the obscurity of your passphrase's formulation gives you any extra security whatsoever.

Re: Evernote hacked

#149

Post by reyan »

UnoriginalGuy wrote: post #65
NoPiece wrote: post #60

Earlier quoted context omitted.

Curious, if the attacker knows what the encryption algorithm is, does it help them at all in breaking it? I.e., does it potentially delay breaking it by not revealing it?

In theory, yes, in practice it is fairly obvious how something is hashed just by eye. Different hash algorithms produce different output (lengths, starting character, and spread). So with some experience you can often tell (or guess and test) what something is hashed with.

The definition of a symmetric cipher requires the cipher text to be (practically) indistinguishable from random. Length is not particularly useful (multiple blocks, different block ciphers with equal block length).

Re: Evernote hacked

#150

Post by santiagoIT »

santiagoIT wrote: post #144

I got the email and reset my password (web browser on desktop). I then launched the MaxOs client app and it asked me to enter the new password, however the iOS app shows its initial loading screen but then just crashes. It never gets around to asking me for the new password. Anyone know a solution to this?

An updated iOS app is available since yesterday. After updating I was able to enter the new password and am back up and running.
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