Re: RESEND: CVE Request: pwgen

[Marcus Meissner <meissner () suse de>]

Hi,

It might just not be that CVE worthy. But I saw no replies...

(CVE worthyness:
It does not fully meet the security expectations of generating
a non-weak password by default....
)

Solar? Kurt?

CIao, Marcus
On Thu, Sep 26, 2013 at 11:11:59AM +1000, Michael Samuel wrote:
> Hi,
>
> No CVEs have been assigned for this, and as far as I can tell no
> distributions have patched.
>
> On 6 June 2013 14:19, Michael Samuel <mik () miknet net> wrote:
>
> > I've done some further analysis of the program after reading the previous
> > thread, and I think there needs to be CVEs and fixes for:
> >
> > - When used from a non-tty passwords are trivially weak by default (first
> > reported by Solar Designer)
> > - Phonemes mode has heavy bias and is enabled by default (first reported
> > by Solar Designer)
> > - Silent fallback to insecure entropy (first reported by Jean-Michel
> > Vourgère) (Debian bug #672241 - tagged as "wishlist")
> > - Secure mode has bias towards numbers and uppercase letters
> >
> > I've attached a patch that fixes most issues - it doesn't solve the bias
> > towards numbers, because it's caused by requiring at-least one number per
> > password - so in an 8 character password there'd have to be 0.1 numbers to
> > avoid bias.  There's an argument to be made for removing the at-least-one
> > rule, but if the system that password is being used with has those rules,
> > it doesn't fix the problem anyway.  Perhaps a separate flag for that?
> >
> > The changes are:
> >
> > - Print a message and abort() of there's trouble opening or reading
> > /dev/urandom (So apport should pick up any packages that have been using
> > insecure entropy)
> > - Make "-s" the default
> > - Add an argument --insecure-phonemes (or -P)
> > - Non-tty passwords are now as secure as tty
> > - Require lower-case characters be present to even out some bias
> > - Pull in passwdqc as a Suggests on the debian package - pwqgen can
> > generate sane random passphrases
> >
> > I can't imagine any reasonable use-case for the non-tty defaults (except
> > maybe combining with espeak as an enhanced interrogation technique), and
> > you can be certain that there's some people out there with it embedded in a
> > script that's generating useless passwords.
> >
> > For phonemes mode in general, the bias is extreme, there are a limited
> > number of possible combinations and it is generally not suitable for
> > security purposes.  I have some fairly detailed analysis of it, but I
> > believe this list has a no-exploits policy...
> >
> > Regards,
> >   Michael