From owner-freebsd-stable Thu Jan 20 17:13:15 2000 Delivered-To: freebsd-stable@freebsd.org Received: from lariat.lariat.org (lariat.lariat.org [206.100.185.2]) by hub.freebsd.org (Postfix) with ESMTP id 6E26115291; Thu, 20 Jan 2000 17:13:05 -0800 (PST) (envelope-from brett@lariat.org) Received: from workhorse (IDENT:ppp0.lariat.org@lariat.lariat.org [206.100.185.2]) by lariat.lariat.org (8.9.3/8.9.3) with ESMTP id SAA11856; Thu, 20 Jan 2000 18:12:37 -0700 (MST) Message-Id: <4.2.2.20000120180821.0188d5c0@localhost> X-Sender: brett@localhost X-Mailer: QUALCOMM Windows Eudora Pro Version 4.2.2 Date: Thu, 20 Jan 2000 18:12:37 -0700 To: Darren Reed From: Brett Glass Subject: Re: bugtraq posts: stream.c - new FreeBSD exploit? Cc: avalon@coombs.anu.edu.au (Darren Reed), imp@village.org (Warner Losh), jamiE@arpa.com (jamiE rishaw - master e*tard), tom@uniserve.com (Tom), mike@sentex.net (Mike Tancsa), freebsd-security@FreeBSD.ORG, freebsd-stable@FreeBSD.ORG, security-officer@FreeBSD.ORG In-Reply-To: <200001210103.MAA20844@cairo.anu.edu.au> References: <4.2.2.20000120174826.01882ad0@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG At 06:03 PM 1/20/2000 , Darren Reed wrote: >If you're using "flags S keep state" or "flags S/SA keep state", >then as far as I'm aware, having read the code, you are safe. This might be a workaround. What rule(s) would have to follow it to block the ACK? >I'm intrigued to know what the bug is. Reading the code, it is >hard to see how you could make a box fall over using it, unless >there were some serious problems in how random TCP ACK's were >handled. My guess is that there's a long code path, or other inefficiency, in the way the ACK is handled. Perhaps a linear search for the right socket instead of one that's more clevery implemented (e.g. search by port, then address, etc.). --Brett To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message