Date: Wed, 29 Aug 2001 22:11:19 +0200 From: "Karsten W. Rohrbach" <karsten@rohrbach.de> To: Peter Pentchev <roam@ringlet.net> Cc: Fernan Aguero <fernan@iib.unsam.edu.ar>, FreeBSD Security <freebsd-security@freebsd.org> Subject: Re: changed /dev/ttys is this normal? Message-ID: <20010829221119.H36662@mail.webmonster.de> In-Reply-To: <20010829171125.G780@ringworld.oblivion.bg>; from roam@ringlet.net on Wed, Aug 29, 2001 at 05:11:25PM %2B0300 References: <20010829102031.A22076@iib005.iib.unsam.edu.ar> <20010829165906.D780@ringworld.oblivion.bg> <20010829171125.G780@ringworld.oblivion.bg>
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--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
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