Date: Sun, 18 Oct 2015 22:06:13 -0600 From: Kurt Seifried <kseifried@...hat.com> To: CVE ID Requests <cve-assign@...re.org>, oss-security <oss-security@...ts.openwall.com> Subject: Prime example of a can of worms 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: A small number of fixed or standardized groups are used by millions of servers; performing precomputation for a single 1024-bit group would allow passive eavesdropping on 18% of popular HTTPS sites, and a second group would allow decryption of traffic to 66% of IPsec VPNs and 26% of SSH servers. -- Kurt Seifried -- Red Hat -- Product Security -- Cloud PGP A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993 Red Hat Product Security contact: secalert@...hat.com
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