nanog mailing list archives

Re: Security team successfully cracks SSL using 200 PS3's and MD5 flaw.


From: Florian Weimer <fw () deneb enyo de>
Date: Sat, 03 Jan 2009 17:23:06 +0100

Then again, I just got yet another Debian DSA mail which has
plaintext download links for new binaries.  The integrity
verification mechanism for said binaries is, you guessed it:
PGP-signed md5sums.

I can assure you that you will continue to receive these messages for
a while (unless you unsubscribe from the relevant mailing lists).

Our rationale is that in order to carry out currently known attacks on
MD5, you need to create a twin of documents, one evil and one
harmless.  In Debian's case, we prepare the data we sign on our
trusted infrastructure.  If someone can sneak in an evil twin due to a
breach, more direct means of attack are available.

In practice, the download links themselves are the larger problem
because users might use them without checking anything.  Eventually,
they will go away, together with the MD5 hashes.  Newer versions of
APT also use the SHA-256 checksums embedded in the Release and
Packages files.


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