Date: Fri, 21 Jan 2000 10:36:39 -0700 From: Brett Glass <brett@lariat.org> To: TrouBle <trouble@netquick.net>, Darren Reed <avalon@coombs.anu.edu.au> Cc: oogali@intranova.net (Omachonu Ogali), security@FreeBSD.ORG Subject: Re: stream.c worst-case kernel paths Message-ID: <4.2.2.20000121102114.01a2dc10@localhost> In-Reply-To: <20000121.16082400@bastille.netquick.net> References: <200001211415.BAA12772@cairo.anu.edu.au> <200001211415.BAA12772@cairo.anu.edu.au>
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At 09:08 AM 1/21/2000 , TrouBle wrote: >So can i get a straight answer, is there yet a patch to fix this >problem under current ?? does it affect current ??? Under CURRENT, the absolute fastest fix is to set tcp_restrict_rst. This ought to hold you until you firewall and/or until there's a patch. You will still see some loading as the kernel does extra work to process the bogus packets; I've made some suggestions for patches that should help this a bit. [Note: some recent postings have pointed out problems with restricting RSTs. They're right; there are some. But that's less important than keeping your systems alive if you're under attack.] Another more general to use IPFilter (not IPFW!) with the rules Darren mentioned earlier: block in quick proto tcp from any to any head 100 pass in quick proto tcp from any to any flags S keep state group 100 pass in all If you use this on your router, it'll protect downstream machines. And it works on all of the BSDs, Solaris, *and* Linux, so it's a more far-reaching fix too. >and 3.3 I don't think 3.3 has tcp_restrict_rst (Guys, correct me here if I'm mistaken), so you'll need to use IPFilter. > and 3.4 ????? 3.4 has tcp_restrict_rst. You can set it in rc.conf. >also is there a way to test the vulnerability is gone after patching >??? I'm sure that stream.c is being sent out on the kiddie IRC channels. --Brett To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
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