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Evernote hacked

blog.evernote.com

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Re: Evernote hacked

#201

Post by cynwoody »

pyre wrote: post #132
fiatpandas wrote: post #124

Earlier quoted context omitted.

>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 demand. I just don't understand the logic behind some of these password rules. Wouldn't it require more effort to explicitly disallow certain characters? Like, they wrote code somewhere that is specifically making…

My understanding is that banks have these weird rules because of the legacy systems that they interface with. I've even heard of new systems built on top of old ones by writing an interface layer on top of the green-screen UI of the old system (i.e. automating the green-screen interaction / screen scraping).

I used to have an account with New England Merchants Bank. My ATM PIN was seven digits. But I noticed that the ATM screen would flash after the first four. A little trial and error revealed that that was all I needed to enter! Comparing notes with friends (this was before the internet) revealed that this little secret was common knowledge.

Subsequently, NEMB got subsumed by successively larger banks, until, finally, Bsnk of America took over. Suddenly, my ATM card wouldn't work! It turned out that they had kept my full PIN on file through the whole chain of acquisitions, but only with B of A did they start comparing ATM PIN entry against the full PIN! My card still worked with the full PIN (which I still remembered, it being an old phone number).

Re: Evernote hacked

#202

Post by raverbashing »

cschneid wrote: post #123
raverbashing wrote: post #115

Earlier quoted context omitted.

No The security of your system can never depend on an attacker not knowing the implementation. Or: Security through obscurity (is no security) Using gimmicks like for example shuffling some characters in the hash may delay some attacks. But the problem is that these techniques are usually done on systems that have no sufficient security. Have a big salt and use PBKDF2 or Bcrypt and you know the exact difficulty of ge…

IMO, you should be doing both. People should use strong bcrypted passwords, with a salt, then ALSO a 'secret' pepper value (long value stored in app code). This adds additional security in the case of a db-only dump being released, and doesn't harm the strength or a full code+db release at all either. Stripping off identifying info from hashes like talked about in this thread doesn't weaken the hash in any way, but i…

Let me try to explain this better

Suppose you're doing the byte shuffling right? Or you split the hash value in two and you concatenate them in the reverse order, something like that.

Now here's the thing: if you have a determined attacker, they will figure out your code does that. So you gain no extra security from it

For a casual attacker this may be a bigger deterrent. Now, this casual attacker may try to create (or already has) an account, for which the password is known. So he goes and compares it trying to figure out your encryption mechanism

It's slightly more difficult than the guy that just used MD5 to hash the passwords (let's assume that's the minimum security people use - "in theory")

So, it's all fine and dandy until you have another 'increase the security' idea that actually decreases the security. And this is more common than you think.

Example: taking the hash and encrypting it (for some choices of hash and encryption)

(Not to mention when people think that because they use this 'improved security scheme' that they invented they can be lax in security elsewhere in the chain)

Re: Evernote hacked

#203

Post by drivebyacct2 »

ams6110 wrote: post #99

we have found no evidence == "we really don't know" Sorry, I'm sure the Evernote tech team is competent, but clearly some marketing spin has been put on this announcement.

If they said, within hours, "We know they took nothing", they'd almost surely be lying, intentionally or otherwise.

Re: Evernote hacked

#204

Post by drivebyacct2 »

DocG wrote: post #136

Not cool. I use evernote for throwaway email passwords. And storing some usernames, without passwords. Just to remember usernames. I wouldn't lose anything, it would be just inconvenient for me.

Maybe use a more appropriate tool? That would be your life way easier anyway? LastPass? 1Pass, etc?

Re: Evernote hacked

#205

Post by drivebyacct2 »

apapli wrote: post #178

Frustrating, I thought they would have done security better than most given the type of information stored here. Does anyone know a decent password keeper? I have a list of logins/passwords for my key sites in a word .doc file stored locally, but given I have a work mac, home mac, tablet and iPhone it really is a pain to access the locally stored file. I thought about saving this file on google drive, but their 2-fac…

>I thought about saving this file on google drive, but their 2-factor auth doesn't seem to apply for drive (only gmail).

Huh? All of Google's logins are through their single-sign-on. TFA protects everything.

Also, please, just use LastPass. I don't know why everyone has it in their head that password managers are a hassle. It's literally easier than using the same password for everything AND more secure.

Re: Evernote hacked

#206

Post by Joeri »

benaiah wrote: post #196
Joeri wrote: post #140

Earlier quoted context omitted.

PBKDF2 is not memory hard, so even with known technology it can be broken relatively easy. Bcrypt seems secure for now, but you shouldn't rely on security through obscurity, which is essentially what putting faith in the irreversability of a hash is. The reality is that if a hashed password leaks, you should assume it will be broken. It's like with bank vaults. They're not designed to withstand attack, just to delay…

Hashes are mathematically proven to be irreversible except through rainbow tables (easily beaten with salting) or brute force. There's no faith needed (well, I suppose that non-mathematicians like myself have to put faith in the math, but I trust the hundreds of independent studies of these algorithms quite well), and it's not anything close to "security through obscurity". That said, you are right. You should always…

Brute force was exactly what i was talking about. It doesn't matter whether a hash is broken through a mathematical flaw, or through improvements in the brute forcing process, if in practice it still gets broken. Once a hash is leaked brute force becomes possible in theory, and what is possible in theory is usually possible in practice with sufficient dedication.

There have been such huge improvements in hashing through tools like hashcat and hardware implementations that i don't think it's unreasonable to distrust hashes. Once a hash is leaked you're essentially hoping that brute forcing it is too high of a cost. Given the history of order of agnitude improvements in hashing speed, i consider it unreasonable to believe that any password database remains safe indefinitely once leaked.

I find your trust in the difficulty of brute forcing a hash just as bizarre as you seem to find my distrust of hashes.

Re: Evernote hacked

#207

Post by j_s »

Terretta wrote: post #109
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…

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…

See also: Steve Gibson's "Password Haystack" https://www.grc.com/haystack.htm

  > everyone has always believed or been told that passwords
  > derived their strength from having “high entropy”. [...]
  > But [...] when the only available attack is guessing, 
  > that long-standing common wisdom is not correct!
(Practical advice for normal users seems to be Steve's raison d'etre; I would be glad to hear anyone share their concerns about his recommendations.)

Re: Evernote hacked

#208

Post by ajanuary »

Volpe wrote: post #195
Terretta wrote: post #170

Earlier quoted context omitted.

First, all this is beside the point. Evernote hasn't understood the concepts of either entropy or human chosen passwords. Rejecting my passphrase and accepting "abc123" is wrong . That's my original post, and that's what you objected to. Computer generated random passwords that nobody's going to use on their mobile phone Evernote client, simply don't figure into normal human use. Our job is to recommend things that c…

While "This phrase is definitely not in the dictionary" is true, every component is. If this sort of password became popular brute forcing passwords would just start using whole word combinations when cracking passwords. i.e a word becomes the equivalent of a character (though from a larger set of characters). Also wouldn't a hash of a long passphrase be longer? (I am completely ignorant the details of hashing algori…

The key idea behind any hashing algorithm is to take inputs of any length and turn them into an output of a fixed length.

Different problem domains have different additional requirements: password hashes want to minimise collisions (multiple inputs hashing to the same output), checksums want to make similar inputs produce wildly different outputs, hashtable/dictionary/map key hashes want to create an even distribution of outputs etc. But the thing common to all hashing algorithms is the output is the same size.

Re: Evernote hacked

#209

Post by patrickaljord »

miles wrote: post #166
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…

Thanks for igniting this discussion, Niten. While digging around, I stumbled onto this tool which others might find helpful: https://github.com/lowe/zxcvbn zxcvbn, named after a crappy password, is a JavaScript password strength estimation library. Use it to implement a custom strength bar on a signup form near you! zxcvbn attempts to give sound password advice through pattern matching and conservative entropy calcul…

If I enter the first 10 characters in regular order of my French azerty keyboard that are &é"'(-è_çà)= I get a top 4/4 score :). Not very good for security.
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