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Re: Security team successfully cracks SSL using 200 PS3's and MD5
From: Marshall Eubanks <tme () multicasttech com>
Date: Sat, 3 Jan 2009 10:36:08 -0500


On Jan 3, 2009, at 9:38 AM, Dorn Hetzel wrote:

Would using the combination of both MD5 and SHA-1 raise the computational
bar enough for now,

I have never seen this recommended (and I do try and follow this).

or are there other good prospects for a harder to crack
hash?

The Federal Information Processing Standard 180-2, Secure Hash Standard, specifies algorithms for computing five cryptographic hash functions — SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512.

SHA-256 is thought to be still safe, unlike SHA-1

http://eprint.iacr.org/2008/271
http://www.schneier.com/blog/archives/2005/02/cryptanalysis_o.html

and its use is recommended by RFC4509.
http://tools.ietf.org/html/rfc4509

So, I would use SHA-256 if possible. (SHA-224 is a truncation of -256 - see rfc3874.)

There is, BTW, a competition to find a replacement.

http://csrc.nist.gov/groups/ST/hash/sha-3/index.html

Regards
Marshall



On Sat, Jan 3, 2009 at 9:35 AM, William Warren <
hescominsoon () emmanuelcomputerconsulting com> wrote:

Dragos Ruiu wrote:


On 2-Jan-09, at 9:56 AM, Robert Mathews (OSIA) wrote:

Joe Greco wrote:

[ ....  ]

Either we take the potential for transparent MitM attacks seriously, or
we do not.  I'm sure the NSA would prefer "not."  :-)

As for the points raised in your message, yes, there are additional
problems with clients that have not taken this seriously.  It is,
however,
one thing to have locks on your door that you do not lock, and another thing entirely not to have locks (and therefore completely lack the ability to lock). I hope that there is some serious thought going on in
the browser groups about this sort of issue.

[ ... ]

... JG


F Y I, see:

SSL Blacklist 4.0 - for a Firefox extension able to detect 'bad'
certificates @
http://www.codefromthe70s.org/sslblacklist.aspx

Best.


Snort rule to detect said...

url: http://vrt-sourcefire.blogspot.com/2009/01/md5-actually-harmful.html

alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"POLICY Weak SSL
OSCP response -- MD5 usage"; content:"content-type:
application/ocsp-response"; content:"2A 86 48 86 F7 0D 01 01 05"; metadata:
policy security-ips drop, service http; reference: url,
www.win.tue.nl/hashclash/rogue-ca/; classtype: policy-violation;
sid:1000001;)

cheers,
--dr

--
World Security Pros. Cutting Edge Training, Tools, and Techniques
Vancouver, Canada  March 16-20 2009  http://cansecwest.com
London, U.K. May 27/28 2009 http://eusecwest.com
pgpkey http://dragos.com/ kyxpgp



Everyone seems to be stampeding to SHA-1..yet it was broken in 2005. So
we trade MD5 for SHA-1?  This makes no sense.





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