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Re: [LUG] Linux - and security

 

On Mon, Nov 5, 2012 at 10:28 PM, Simon Waters wrote:
> I think the idea security and conflicts with usability or convenience is
> overstated.

Sure, I oversimplified. But in the short term, almost every security
measure I take is inconvenient. It'd be more convenient if I could
take money out of an ATM by just showing it my bank card. It would of
course cause a lot more inconvenience in the longer term.

> We have already seen large lists of hashed passwords stolen from big
> providers, and various friends were changing passwords they had reused
> at lastfm, linkedin and elsewhere. This is part of what motivated me to
> change the passwords so extensively.
>
> I agree about rapid password guessing, I think this is unlikely,
> although I could believe it might be an issue for my twitter password.
> It is not inconceivable a botnet might have guessed the password, and
> I'm guessing whilst twitter try and mitigate that it must be hard if the
> botnet is large enough.

I seriously doubt that. I just looked up your Twitter account, unless
you've lost 99.9% of your followers recently, you don't seem to be a
very prominent target. Not to mention that only with a very prominent
account (someone with 1,000,000+ followers) it'd be worth going
through a dictionary of passwords. Even if you control a huge botnet.
You can do 'better' things with these.

And Twitter doesn't allow too many login attempts either:
https://support.twitter.com/articles/63510-i-m-locked-out-after-too-many-login-attempts

> But I don't think that is the threat here, the danger if you reuse
> passwords is it will become known by any means, and will be either in
> their list for new attacks or used in a targeted attack. e.g. someone
> will look to see if the email/password combination was reused elsewhere
> on the net.

Yes password reuse is really bad. I'd say it is a lot worse than using
weak passwords, yet most security people focus on the latter. This
shouldn't be an either/or choice, but if for some hypothetical reason
you were faced with a choice between one very strong password for
everything, or a different weak one for each service you use, you
should always go for the latter.

> If you have a list of 2.5 million hashes from lastfm, then the question
> is not how hard it is to crack a specific password but how many
> passwords fall out as low hanging fruit.

Good point. That's why hashes should be salted, but at least those of
LinkedIn weren't. I guess those of Last.fm weren't either.

But again, I did not argue against using strong passwords. I'm just
worried that by focusing on password security, people focus too much
on something that may be the cause of about 5% of account compromises.

The problem with the remaining 95% is that it's a lot less hard to
turn into clear advise to users: "don't use machines with keyboards"
or "don't use services with XSS vulnerabilities" aren't very helpful.

Mind you, I don't really have a solution to that problem. Other than
tell people if their account is compromised to change their password
but then don't assume the problem has been fixed.

Martijn.

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