From owner-freebsd-security Wed Aug 29 13:11: 5 2001 Delivered-To: freebsd-security@freebsd.org Received: from mail.webmonster.de (datasink.webmonster.de [194.162.162.209]) by hub.freebsd.org (Postfix) with SMTP id 7B19C37B403 for ; Wed, 29 Aug 2001 13:10:59 -0700 (PDT) (envelope-from karsten@rohrbach.de) Received: (qmail 43136 invoked by uid 1000); 29 Aug 2001 20:11:19 -0000 Date: Wed, 29 Aug 2001 22:11:19 +0200 From: "Karsten W. Rohrbach" To: Peter Pentchev Cc: Fernan Aguero , FreeBSD Security Subject: Re: changed /dev/ttys is this normal? Message-ID: <20010829221119.H36662@mail.webmonster.de> Mail-Followup-To: "Karsten W. Rohrbach" , Peter Pentchev , Fernan Aguero , FreeBSD Security References: <20010829102031.A22076@iib005.iib.unsam.edu.ar> <20010829165906.D780@ringworld.oblivion.bg> <20010829171125.G780@ringworld.oblivion.bg> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-md5; protocol="application/pgp-signature"; boundary="it/zdz3K1bH9Y8/E" Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20010829171125.G780@ringworld.oblivion.bg>; from roam@ringlet.net on Wed, Aug 29, 2001 at 05:11:25PM +0300 X-Arbitrary-Number-Of-The-Day: 42 X-URL: http://www.webmonster.de/ X-Disclaimer: My opinions do not necessarily represent those of my employer X-Work-URL: http://www.ngenn.net/ X-Work-Address: nGENn GmbH, Schloss Kransberg, D-61250 Usingen-Kransberg, Germany X-Work-Phone: +49-6081-682-304 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 --it/zdz3K1bH9Y8/E Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Peter Pentchev(roam@ringlet.net)@2001.08.29 17:11:25 +0000: > ..but actually, it might be wise if Tripwire would warn you about > changes in *anything* but the owner on terminal devices. Also, > it would be wise to have it warn you for the appearance of *new* > files looking like terminal devices. I've seen more than one > rootkit which installed a setuid shell or a config file or whatever > as /dev/ttySomething, or as a replacement for one of the higher-numbered > tty devices (in the hope that those are reached only very rarely, > and this would go unnoticed for quite some time). i think it would make sense to monitor /dev for non-devnodes except the MAKEDEV and MAKEDEV.local which should be monitored as plain file. rohrbach@WM:datasink[/dev]139% find . -type f =2E/MAKEDEV.local =2E/MAKEDEV to sum it up (4.3-STABLE): 2 files MAKEDEV/MAKEDEV.local 1 dir fd/ containing 64 chardevs hundreds chardevs all the devnodes depending on config some symlinks depending on audio config et al. 0 blockdevs 0 fifos 0 sockets this could serve as a basis for a subtractive ruleset for monitoring /dev cheers, /k --=20 > "I think pop music has done more for oral intercourse than anything else > that has ever happened, and vice versa." --Frank Zappa KR433/KR11-RIPE -- WebMonster Community Founder -- nGENn GmbH Senior Techie http://www.webmonster.de/ -- ftp://ftp.webmonster.de/ -- http://www.ngenn.n= et/ karsten&rohrbach.de -- alpha&ngenn.net -- alpha&scene.org -- catch@spam.de GnuPG 0x2964BF46 2001-03-15 42F9 9FFF 50D4 2F38 DBEE DF22 3340 4F4E 2964 B= F46 Please do not remove my address from To: and Cc: fields in mailing lists. 1= 0x --it/zdz3K1bH9Y8/E Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (FreeBSD) Comment: For info see http://www.gnupg.org iD8DBQE7jUxnM0BPTilkv0YRAuTjAJ0albGRIYRhEc8KaB8UANr0tNR8MwCfcB4S wgLabOjId+WldAotBNE/h/8= =VP/Q -----END PGP SIGNATURE----- --it/zdz3K1bH9Y8/E-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message