From owner-freebsd-security@FreeBSD.ORG Wed Feb 3 18:14:40 2010 Return-Path: Delivered-To: freebsd-security@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1585E1065672 for ; Wed, 3 Feb 2010 18:14:40 +0000 (UTC) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.freebsd.org (Postfix) with ESMTP id AA4408FC1D for ; Wed, 3 Feb 2010 18:14:39 +0000 (UTC) Received: from apollo.backplane.com (localhost [127.0.0.1]) by apollo.backplane.com (8.14.4/8.14.1) with ESMTP id o13IEZie081413; Wed, 3 Feb 2010 10:14:35 -0800 (PST) Received: (from dillon@localhost) by apollo.backplane.com (8.14.4/8.13.4/Submit) id o13IEYqk081411; Wed, 3 Feb 2010 10:14:34 -0800 (PST) Date: Wed, 3 Feb 2010 10:14:34 -0800 (PST) From: Matthew Dillon Message-Id: <201002031814.o13IEYqk081411@apollo.backplane.com> To: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= References: <20100128182413.GI892@noncombatant.org> <9d972bed1001281324r29b4b93bw9ec5bc522d0e2764@mail.gmail.com> <20100128224022.396588dc@gumby.homeunix.com> <201001282311.o0SNBWp4003678@apollo.backplane.com> <86ock95bls.fsf@ds4.des.no> <201002011824.o11IOxjQ045906@apollo.backplane.com> <86y6jacyxb.fsf@ds4.des.no> Cc: freebsd-security@freebsd.org Subject: Re: PHK's MD5 might not be slow enough anymore X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 Feb 2010 18:14:40 -0000 :If you're serious about strong authentication, use time-synchronized OTP :tokens. Oh wait, you can't, because you need PAM and ChallengeResponse :to mediate between the user and the backend, which usually acts like a :Radius server. Too bad. : :DES :-- :Dag-Erling Smørgrav - des@des.no The default PAM setting in OpenSSH is 0. Line 138 servconf.c in openssh-5.3p1 (that's the portable version). The default comment in sshd_config in openssh-5.3.p1 from ftp.openssh.com and is condusive to the state of the code, which is the reverse of what FreeBSD has done. I didn't bother to go check earlier releases to see if it was different in the past, but that seems to be the current state. Frankly I'm a bit surprised that you are even trying to defend the FreeBSD changes. They are clearly less secure. All you had to do was adjust the default sshd_config. PAM is black-magic for most users, the last thing you want to do is suggest that the general user base make changes to PAM configuration files verses the far more user friendly sshd_config. The vast majority of BSD users don't need PAMs capabilities when it comes to ssh. Having it disabled by default is more appropriate. For that matter, your suggestion that all users use some esoteric feature and mess with PAM configuration files as a solution instead of changing the far more user-friendly sshd_config is just bad advise to users. It seems to me that you are setting defaults for the convenience of a minority of people when they should be set for the convenience of the majority. And if you are really going to insist on changing the option around the least you could have done was uncomment the related options and set them to a definitive 'no' value (that would be ChallengeResponse at the very least) when you made the other changes. The whole point of my original posting was to provide an alternative to users concerned with password attacks on ssh and you basically turned it into a personal attack. You need to grow up. -- In anycase, I think Mr Barton's posting was excellent. We already ship with PasswordAuthentication set to 'no' and, of course, PAM is disabled by default, but I am going to make further adjustments to our sshd_config based on Doug's suggestions plus I will also uncomment ChallengeResponseAuthentication and set that to 'no' too as a further safety measure. The plain fact of the matter is that allowing short user passwords over-the-wire for a shell login, whether in the clear or tunneled, can no longer be considered a reasonable default in this day and age. -Matt Matthew Dillon