Re: gmail security is a joke

[Peter Beckman <beckman () angryox com>]

LinkedIn used SHA-1, a fast algorithm. At 350-billion guesses per second on
the mentioned rig for fast algorithms, yeah, you can get through a lot of
passwords quickly. Hopefully LinkedIn has changed their ways.

In that same article:

    "...functions such as Bcrypt, PBKDF2, and SHA512crypt are designed to
     expend considerably more time and computing resources to convert
     plaintext input into cryptographic hashes. As a result, the new
     cluster, even with its four-fold increase in speed, can make only
     71,000 guesses against Bcrypt..."

And if you use a different salt for each password stored with Bcrypt, the
hacker must test each password separately -- no rainbow tables here.

Unfortunately they don't say how many iterations of Bcrypt equals 71,000,
since you can add more iterations of the algorithm. An example cipher text
from bcrypt:

    $2a$13$Ejtc1pVjyLkZn4eU9FGCg.gOQ3QtbWOsUOvSUKbU2anywhoO04ESy

$2a$ indicates the blowfish algorithm, $13$ is the cost factor (number of
iterations), the first 22 chars after are the salt and the rest is the
cipher text. The higher the number of iterations, the harder
computationally it is to go from a password to the cipher text. As hardware
improves, the iterations should increase.

I was thinking about using the last 2 digits of the year as the cost
factor, but that might not scale with hardware linearly.

Bcrypt or PBKDF2 with random salts per password is really what anyone
storing passwords should be using today.

Beckman

On Wed, 27 May 2015, Rich Kulawiec wrote:

> On Wed, May 27, 2015 at 01:51:35PM -0400, Barry Shein wrote:
> > Getting a copy of the database of hashes and login names is basically
> > useless to an attacker.
>
> Not any more, if the hash algorithm isn't sufficiently strong:
>
>         25-GPU cluster cracks every standard Windows password in <6 hours
>         http://arstechnica.com/security/2012/12/25-gpu-cluster-cracks-every-standard-windows-password-in-6-hours/
>
> Quoting:
>
>         "Gosney used the machine to crack 90 percent of the 6.5 million
>         password hashes belonging to users of LinkedIn."
>
> Consider as well that not all attackers are interested in all accounts:
> imagine what this system (or a newer one, this is 2.5 years old) could
> do if focused on only one account.
>
> And of course epidemic password reuse means that cracked passwords
> are reasonably likely to work at multiple sites.
>
> And even if passwords aren't reused, there have now been so many
> breaches at so many places resulting in so many disclosed passwords
> that a discerning attacker could likely glean useful intelligence
> by studying multiple password choices made by a target.  (We're all
> creatures of habit.)
>
> ---rsk

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Peter Beckman                                                  Internet Guy
beckman () angryox com                                 http://www.angryox.com/
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