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McGill will double your password if you don’t do it first

mcgill.ca

71–80 of 152 posts

Re: McGill will double your password if you don’t do it first

#71

After all of this effort, they're still limiting passwords to 18 characters? Why would they do that?

I't because they are still storing passwords in cleartext... If they were hashing passwords (which is the correct way to do it) there would be no limit.

Re: McGill will double your password if you don’t do it first

#72
post #69

Earlier quoted context omitted.

I'm not sure, but there may be some hash functions for which H(concat(a, a)) = F(H(a)). I'd worry a little about their security in some contexts - particularly if that generalized beyond just duplication, it seems likely vulnerable to length extension attacks if used for HMAC, &c - but for password hashing it might be fine and would clearly be better than plain text. It's not impossible they were already using a hash…

there may be some hash functions for which H(concat(a, a)) = F(H(a)) If H is secure then F is not computable. If they can do a trick like this then their hashing is no good. Another possibility would be Yeah, you can approach it like a puzzle and figure out what crazy set up they could have, but Occam's Razor has to apply at some point. I'm betting they did the dumb thing, not the strange thing that is mostly pointle…

"If H is secure then F is not computable. If they can do a trick like this then their hashing is no good."

Can you point to something more than assertion, here?

"Yeah, you can approach it like a puzzle and figure out what crazy set up they could have, but Occam's Razor has to apply at some point. I'm betting they did the dumb thing, not the strange thing that is mostly pointless."

It's mostly pointless, but it's increasingly common knowledge that the dumb thing is dumb. It's more subtle that the pointless thing is pointless. If I had to bet, I'd also bet that they did the dumb thing, I just think it's marginally less conclusive than had been implied.

Re: McGill will double your password if you don’t do it first

#73
post #9

The fact that they're able to "double your password" is a bad sign. Here's what this implies to me: * McGill had a database of everyone's password in plaintext at the time of Heartbleed * McGill is concerned about mitigating possible security compromises due to Heartbleed, including these plaintext passwords, which if they were compromised were compromised all at once * Despite this concern, McGill still has a databa…

A better way to do this would have been:

* hash current passwords with a salt, unique to each password entry, and throw away the plaintext entries.

* keep a history of hashes per user, to prevent changing to a past password

* ensure fair complexity of the incoming password

* once the deadline has been reached, force users who have not yet changed their password to do a password reset via an online form

* never, ever again think that doubling a password is a proper way to fix a security issue, ever...

Re: McGill will double your password if you don’t do it first

#75
post #9

The fact that they're able to "double your password" is a bad sign. Here's what this implies to me: * McGill had a database of everyone's password in plaintext at the time of Heartbleed * McGill is concerned about mitigating possible security compromises due to Heartbleed, including these plaintext passwords, which if they were compromised were compromised all at once * Despite this concern, McGill still has a databa…

They can put a flag on the database and check that the cleartext you send them when logging in is doubled before hashing half of it. I can't count how many times I've seen something that could easily be done at login time and people conclude that the service must be storing plaintext or multiple hashes. This isn't even a direct security measure in the first place. This is to annoy people into updating their passwords…

Even if they 'check that the cleartext you send them when logging in is doubled before hashing half of it' and calculate hash of the doubled string, what will they check it against? They don't have the hash of double the string until and unless they were storing the plain-text.

Re: McGill will double your password if you don’t do it first

#76

Earlier quoted context omitted.

There's also the "exactly 8" limit increased to "8 to 18". Why even have those limits? If you're hashing it there's no reason to have a limit at all.

I've always wondered this... So many organizations do this.

Typically compatibility with legacy systems

Re: McGill will double your password if you don’t do it first

#78
post #52

Earlier quoted context omitted.

Doubling doesn't provide a benefit, no matter how well they hash or don't hash.

It annoys people into updating their password, for one.

Which they could of accomplished with a password reset via email.

Re: McGill will double your password if you don’t do it first

#79
post #9

The fact that they're able to "double your password" is a bad sign. Here's what this implies to me: * McGill had a database of everyone's password in plaintext at the time of Heartbleed * McGill is concerned about mitigating possible security compromises due to Heartbleed, including these plaintext passwords, which if they were compromised were compromised all at once * Despite this concern, McGill still has a databa…

There's also the "exactly 8" limit increased to "8 to 18". Why even have those limits? If you're hashing it there's no reason to have a limit at all.

I always thought that the max is there to discourage users from setting passwords so long they can't remember them (and instead write them down on a post-it that's right on the monitor).

Re: McGill will double your password if you don’t do it first

#80
post #9

The fact that they're able to "double your password" is a bad sign. Here's what this implies to me: * McGill had a database of everyone's password in plaintext at the time of Heartbleed * McGill is concerned about mitigating possible security compromises due to Heartbleed, including these plaintext passwords, which if they were compromised were compromised all at once * Despite this concern, McGill still has a databa…

There's also the "exactly 8" limit increased to "8 to 18". Why even have those limits? If you're hashing it there's no reason to have a limit at all.

I believe old versions of mailman fall on their face when using pw more than 8 chars.
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