From owner-freebsd-security Wed Oct 9 12:53:42 2002 Delivered-To: freebsd-security@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1D8BD37B401; Wed, 9 Oct 2002 12:53:40 -0700 (PDT) Received: from obsidian.sentex.ca (obsidian.sentex.ca [64.7.128.101]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2B7DA43E8A; Wed, 9 Oct 2002 12:53:37 -0700 (PDT) (envelope-from mike@sentex.net) Received: from simian.sentex.net (pyroxene.sentex.ca [199.212.134.18]) by obsidian.sentex.ca (8.12.6/8.12.6) with ESMTP id g99JrX8g051088; Wed, 9 Oct 2002 15:53:34 -0400 (EDT) (envelope-from mike@sentex.net) Message-Id: <5.1.1.6.0.20021009154208.05e43d98@marble.sentex.ca> X-Sender: mdtpop@marble.sentex.ca X-Mailer: QUALCOMM Windows Eudora Version 5.1.1 Date: Wed, 09 Oct 2002 15:54:27 -0400 To: Kris Kennaway From: Mike Tancsa Subject: Re: Am I downloading what I think I am (was Re: I doubt that this affects FreeBSD, but FYI Cc: security@FreeBSD.ORG In-Reply-To: <20021009193602.GG84472@xor.obsecurity.org> References: <20021009193436.GF84472@xor.obsecurity.org> <4.3.2.7.2.20021008174734.029e9e00@localhost> <5.1.1.6.0.20021009130608.0655d7f8@marble.sentex.ca> <20021009193436.GF84472@xor.obsecurity.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed X-Virus-Scanned: By Sentex Communications (obsidian/20020517) X-Spam-Status: No, hits=-4.7 required=5.0 tests=IN_REP_TO,REFERENCES,SPAM_PHRASE_00_01 version=2.41 Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org At 12:36 PM 09/10/2002 -0700, Kris Kennaway wrote: >On Wed, Oct 09, 2002 at 01:13:51PM -0400, Mike Tancsa wrote: > > > One thing to note about MD5 sums, is that if someone broke into an ftp site > > and uploaded a trojaned file, why not upload a new matching MD5 checksum > > file as well ? > >MD5 sums distributed _with_ the binary are a guard against corruption Hi, Sorry, I should have been more clear. I was speaking more to the general issue of a user downloading both the binary and checksum from the same source as is / was the case with ftp.sendmail.org. I really like how the ports work because they do add a bit of extra security. Like you said, its not perfect, but it does help. Actually, I am somewhat surprised there is not some more widely used mechanism. e.g. for integrity checksums, why not have it on a totally separate server run on a totally separate network by totally separate admins. data one place, checksum another. This way to tamper with the package, you would need to compromise two different systems. A sort of checksum clearing house ? ---Mike To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message