From owner-freebsd-security Wed Nov 3 12:58: 6 1999 Delivered-To: freebsd-security@freebsd.org Received: from quaggy.ursine.com (lambda.blueneptune.com [209.133.45.179]) by hub.freebsd.org (Postfix) with ESMTP id 5167214A12 for ; Wed, 3 Nov 1999 12:57:47 -0800 (PST) (envelope-from fbsd-security@ursine.com) Received: from michael (lambda.ursine.com [209.133.45.69]) by quaggy.ursine.com (8.9.2/8.9.3) with ESMTP id MAA85642 for ; Wed, 3 Nov 1999 12:57:45 -0800 (PST) Message-ID: <199911031257450300.612205D4@quaggy.ursine.com> References: X-Mailer: Calypso Version 3.00.00.13 (2) Date: Wed, 03 Nov 1999 12:57:45 -0800 From: "Michael Bryan" To: freebsd-security@freebsd.org Subject: Fwd: Sendmail 8.x.x - any user may rebuild aliases database Content-Type: text/plain; charset="us-ascii" Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Spotted on BugTraq today. ***** Forwarded Message From BugTraq ***** Sendmail up to recent 8.9.x versions - any user may pass -bi parameter to /usr/sbin/sendmail. This will result in aliases database rebuild. IMHO there's no reason to allow such things, but no matter - something rather stupid is done during rebuild: 5366 open("/etc/aliases.db", O_RDWR|O_TRUNC) = 6 What a bad luck! There's approx 0.1 sec delay due to /etc/aliases processing (on my system). Meantime, luser might deliver any signals to sendmail process... SIGKILL is quite good. After that, /etc/aliases.db will be left in unusable state (no EOF marker), causing DoS: 220 Marchew ESMTP Mail Service at nimue.ids.pl ready. mail from: myself 451 Cannot open hash database /etc/aliases: Invalid argument rcpt to: lcamtuf 503 Need MAIL before RCPT Exploit is trivial. _______________________________________________________________________ Michal Zalewski [lcamtuf@ids.pl] [link / marchew] [dione.ids.pl SYSADM] [Marchew Industries] ! [http://lcamtuf.na.export.pl] bash$ :(){ :|:&};: [voice phone: +48 22 813 25 86] <=-=> [cellular phone: +48 501 4000 69] Iterowac jest rzecza ludzka, wykonywac rekursywnie - boska [P. Deutsch] ***** End Forwarded Message ***** Michael Bryan fbsd-security@ursine.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message