oss-sec mailing list archives

Re: Prime example of a can of worms


From: Loganaden Velvindron <loganaden () gmail com>
Date: Thu, 22 Oct 2015 04:36:12 +0000

On Mon, Oct 19, 2015 at 4:06 AM, Kurt Seifried <kseifried () redhat com> wrote:

So in light of:

https://weakdh.org/imperfect-forward-secrecy-ccs15.pdf

and


https://www.eff.org/deeplinks/2015/10/how-to-protect-yourself-from-nsa-attacks-1024-bit-DH

I would suggest we minimally have a conversation about DH prime security
(e.g. using larger 2048 primes, and/or a better mix of primes to make
pre-computation attacks harder). Generating good primes is not easy from
what I've seen of several discussions, my fear would be that people try to
fix this by finding new primes that turn out to be problematic.

Secondly I would also suggest we seriously look at assigning a CVE to the
use of suspected compromised DH primes. Despite the fact we don't have
conclusive direct evidence (that I'm aware of, correct me if there is any
conclusive evidence) I think in this case:

1) the attack is computationally feasible for an organization with
sufficient funding
2) the benefit of such an attack far, far, FAR outweighs the cost for
certain orgs, from the paper:


I think that it's important for organizations who are providing services
that are considered critical to the stability of the Internet to audit &
take corrective measures for all of their impacted services.

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