From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262232AbTJAOR2 (ORCPT ); Wed, 1 Oct 2003 10:17:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262241AbTJAOR1 (ORCPT ); Wed, 1 Oct 2003 10:17:27 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:29327 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S262232AbTJAOR0 (ORCPT ); Wed, 1 Oct 2003 10:17:26 -0400 Date: Wed, 1 Oct 2003 15:17:18 +0100 From: viro@parcelfarce.linux.theplanet.co.uk To: Makan Pourzandi Cc: Pavel Machek , linux-kernel@vger.kernel.org, Axelle Apvrille , Vincent Roy , David Gordon , socrate@infoiasi.ro Subject: Re: [ANNOUNCE] DigSig 0.2: kernel module for digital signature verification for binaries Message-ID: <20031001141718.GT7665@parcelfarce.linux.theplanet.co.uk> References: <3F733FD3.60502@ericsson.ca> <20031001102631.GC398@elf.ucw.cz> <3F7AD795.1040001@ericsson.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3F7AD795.1040001@ericsson.ca> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 01, 2003 at 09:33:09AM -0400, Makan Pourzandi wrote: > Third, the intruder now has access to the system, he cannot execute the > code he brought in with himself (not signed) or he cannot bring it in > (c.f. above). So he needs to compile the code on the system. AFAIK, for > the absolute majority of servers the admins remove all compilers > (specially gcc) on all servers. this is for several different security > reasons (I don't want to get there). therefore, the above hypothesis > gets even more difficult to realize. Don't be ridiculous. It's trivial to exploit a local buffer overrun in one of your signed binaries and have the shellcode mmap the rest. All pre-built, of course. > Last, but I believe the most important, the level of difficulty of > execution of such an attack is much higher than the average knowledge > level of many script kiddies. The absolute majority of attackers have > little or absolutely not any knowledge of the operating systems in > general and linux in particular, let aside the knowledge of writing a C > program, calling mmaps in that progam and run the malicious code to gain > access as root, then remove the module to execute a classical attack. > > There is no such thing as 100% secure system, digsig increases the level > of security of the system as it just makes it much more difficult for > the intruder to succeed in his/her attack. Rubbish. You don't need to compile anything locally and the rest will be done once by some wanker with half a clue and then repeated by wankers without a clue (aka script kiddies).