The Pointlessness of the MD5 "attacks"

[Ben Laurie]

Dan Kaminsky's recent posting seems to have caused some excitement, but 
I really can't see why. In particular, the idea of having two different 
executables with the same checksum has attracted attention.

But the only way I can see to exploit this would be to have code that 
did different things based on the contents of some bitmap. My contention 
is that if the code is open, then it will be obvious that it does 
"something bad" if a bit is tweaked, and so will be suspicious, even if 
the "something bad" is not triggered in the version seen.

So, to exploit this successfully, you need code that cannot or will not 
be inspected. My contention is that any such code is untrusted anyway, 
so being able to change its behaviour on the basis of embedded bitmap 
changes is a parlour trick. You may as well have it ping a website to 
find out whether to misbehave.

Cheers,

Ben.

-- 
http://www.apache-ssl.org/ben.html       http://www.thebunker.net/

"There is no limit to what a man can do or how far he can go if he
doesn't mind who gets the credit." - Robert Woodruff

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