This will not yield the password; it will yield a value that, when hashed,
will yield the same MD5 checksum. Hashes can yeild the same result from
various inputs. These are called hash collisions. If you are performing a
simple MD5 hash without any additional transformations on the data then an
identified value that will yield such a hash collision would suffice as the
password. This is why authentication using only a hash algorithm is not
always the best way to do it.
Yvan Boily
Seccuris
> -----Original Message-----
> From: Bénoni MARTIN [mailto:Benoni.MARTIN_at_libertis.ga]
> Sent: Thursday, July 01, 2004 12:19 PM
> To: Toro, Daniel; Stan Guzik; Dave Andrews;
> webappsec_at_securityfocus.com; forensics_at_securityfocus.com
> Subject: RE: Securing encrypted data in RAM vs MSSQL
>
> Well, there is always a way to recover the real password or
> login from a hash...the matter's is the time it will take!
>
>
> The method to "dehash" a hash is quite simple: as theorically
> a hash_1 can be produced by a single pass_1/login_1/..., we
> can create a huge amount of random pass_2/logins_2/..., hash
> them with MD5/SHA-1/... and then compare each of them with
> our hash_1. ASA the two hashes are the same, we can pick up
> the pass/login/... which produced hash_2. Quite simple but
> really long to perform.
>
> BTW, Cain & Abel, John the Ripper and Crack can perform such
> recoveries... :)
>
>
>
> -----Message d'origine-----
> De : Toro, Daniel [mailto:tcvx_at_taconvino.cl]
> Envoyé : jeudi 1 juillet 2004 17:33
> À : Stan Guzik; Dave Andrews; webappsec_at_securityfocus.com;
> forensics_at_securityfocus.com
> Objet : Re: Securing encrypted data in RAM vs MSSQL
>
> Related to point 3.A below: Is it really necessary to delete
> the data if it's encrypted with a one-way encryption algo
> like MD5? There's no way to recover data from the message
> digest produced by MD5 that I know of. Of course, I don't
> know everithing. :-)
>
>
>
> On Thu, 1 Jul 2004 09:24:55 -0400, Stan Guzik <SGuzik_at_ImmediaTech.com>
> wrote:
>
> > See reply below.
> >
> > Good Luck,
> > Stan
> >
> > -----Original Message-----
> > From: Dave Andrews [mailto:dave_at_pint.com]
> > Sent: Wednesday, June 30, 2004 8:52 PM
> > To: webappsec_at_securityfocus.com; forensics_at_securityfocus.com
> > Subject: Securing encrypted data in RAM vs MSSQL
> >
> > Hello All,
> >
> > Is anyone aware of a way to store encrypted sensitive data
> in RAM for
> > access via a web application using ASP?
> >
> > 1) You can create an ActiveX EXE that will remain in
> memory. When the
> > web application loads instantiate the ActiveX EXE and
> access it like
> > any other dll.
> >
> >
> > It would be posted in the same
> > manner.
> > Is storing in RAM preferable to using an encrypted
> database, in this
> > case SQL 2000?
> >
> > 2) It depends on the application and network environment.
> This is a
> > difficult question to answer not knowing more details.
> >
> > Is there anyway to securely delete or timeout the data
> after a certain
> > period of time?
> >
> > 3) A. If you store the data in memory you can kill the
> instance of the
> > object and the memory will be released. Depending on the
> type of RAM
> > you have the data may or may nor remain on the chip for a
> short period
> > of time.
> >
> > B. I'm not sure how to easily delete data from a SQL Server DB and
> > not have it recovered by a forensics tool. A difficult way
> of doing
> > it is to compact the SQL Server DB which will shrink the DB
> file size
> > and then use PGP Freespace Wipe to permanently delete any
> residual data on the
> > hard drive. This is a good question, anybody know of a
> better way?
> >
> > C. PGP Wipe is a good tool with API support to delete files so a
> > forensics tool can't recover the data.
> >
> > If you discard the data are there potential problems with
> California
> > SB
> > 1386 and being able to track intrusions and possible data
> compromise?
> >
> > I'm not a developer, but want a better solution than what the
> > developers and client have proposed.
> >
> > Thanks in advance
> > Dave Andrews
> > PINT, Inc
> > 2105 Garnet Ave. Suite E
> > San Diego, CA 92109
> > TEL 858.270.2086
> > FAX 858.270.0410
>
>
>
> --
> TCV
>
>
>
>
Received on Jul 01 2004
Intro
