Re: Validation flaw addressed in version 2.14

I don't think you can fix this and maintain backwards 
compatibility.  I think you have to choose.

And security should win.

You could have a transition version that supports the old version but 
nags people to use the new version, or something like that.  Or a 
version that accepts the old version and then forces the user to use 
the new version.  But in the end backwards compatibility has to be broken.

At 02:31 PM 11/23/2005, Rony Shapiro wrote:

>The good folks at elcomsoft have posted an item regarding a flaw in the
>passphrase validation for all versions of PasswordSafe.
>(http://seclists.org/lists/vulnwatch/2005/Oct-Dec/0046.html)
>
>Briefly, it's possible to take advantage of the database structure to bypass
>the deliberately slow "key stretching" method used to verify the user's
>passphrase, enabling a faster brute-force dictionary attack than was
>intended by the designers.
>
>In release 2.14, I've implemented a partial fix to this, basically replacing
>fixed data with randomness wherever possible in the first block. This is a
>partial fix, but it's the most I can do without breaking backwards
>compatability with existing implementations (and it seems that I've already
>broken compatability with the Java version...).
>
>I'd like to ask this list for suggestions for (1) a better solution that
>would keep compatability with previous versions (that is, that previous
>versions 2.x of PasswordSafe will be able to read the new database, and (2)
>a complete solution, unencumbered by backwards-compatability (that is, a new
>version of the database format).
>
>Thanks to Jeff & Hagai for bringing the vulnwatch posting to my attention.
>
>         Cheers,
>
>                 Rony
>
>P.S. - I've decided not to announce this to the user's mailing list for two
>reasons: 1. The issue is a bit subtle and therefore difficult to explain.
>Conversely, it's *very* easy to misunderstand as "passwordsafe's security
>is/was broken". 2. The fix isn't a complete solution to the problem (yet).
>Of course,



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