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Remotely Crash OpenBSD
*no comment* writes "If you are running OpenBSD on your IPv6 install, it might be time to upgrade to -current. (just kidding) There is, however, a way to crash OpenBSD 3.4 with a couple of simple IPv6 commands. Georgi Guninski, found the problem. To quote Theo, 'it is just a crash.'" It is unknown if the bug could be used to execute arbitrary code, but it does require patching a Linux kernel (or rolling your own network stack) to exploit.
I think it's time to upgrade to windows.
I am defenseless. Use your button. Mod me down with all of your hatred.
Or can OpenBSD still boast "Only one remote hole in the default install, in more than 7 years!" ?
--
Society has traditionally always tried to find scapegoats for its problems. Well, here I am.
I'm thinking that if someone from Microsoft stated "It's just a crash" the editors here would be just a touch more sarcastic...
I know that the problem has been fixed in -current, but I run a production box that I refuse to bring up to -current. There's no patch or even a mention of this problem on the errata page.
What's a sane admin to do?
You have to have a modified ipv6 stack in order to exploit this bug, not to fix it. I can remotely crash your ipv6 enabled openbsd if I modify my linux kernel. Capisce?
Remote openbsd crash with ip6, yet still openbsd much better than windows
i ng in this document may change without notice.
:
/* we coulnd't care less */ //joro
i net6/ip6_output.c e t/tcp_output.c?sortby=date
Systems affected:
tested on openbsd 3.4
not clear about netbsd
freebsd not vulnerable
Risk: Medium
Date: 4 February 2004
Legal Notice:
This Advisory is Copyright (c) 2004 Georgi Guninski.
You may distribute it unmodified.
You may not modify it and distribute it or distribute parts
of it without the author's written permission - this especially applies to
so called "vulnerabilities databases" and securityfocus, microsoft, cert
and mitre.
If you want to link to this content use the URL:
http://www.guninski.com/obsdmtu.html
Anyth
Disclaimer:
The information in this advisory is believed to be true though
it may be false.
The opinions expressed in this advisory and program are my own and
not of any company. The usual standard disclaimer applies,
especially the fact that Georgi Guninski is not liable for any damages
caused by direct or indirect use of the information or functionality
provided by this advisory or program. Georgi Guninski bears no
responsibility for content or misuse of this advisory or program or
any derivatives thereof.
Description:
It is possible to remotely crash openbsd 3.4 if the host receives icmpv6
and there is a listening tcp port.
quoting de raadt: "it is just a crash."
remote crash which screws the kernel.
unknown whether this may be exploited for code execution.
Details:
The problem is triggered by setting small ipv6 mtu and then doing tcp
connect.
How to reproduce:
Patch linux kernel 2.4.24 net/ipv6/icmp.c
case ICMPV6_ECHO_REPLY:
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, 68, skb->dev);
then:
ping6 openbsd
ssh -6 openbsd
Workaround:
It is believed that openbsd current is not vulnerable.
netbsd current also seems to have related changes.
check:
http://www.openbsd.org/cgi-bin/cvsweb/src/sys/net
http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/netin
Vendor status:
open, net and free bsd were notified Sun, 1 Feb 2004 16:35:56 +0200
Georgi Guninski
http://www.guninski.com
Great, now when I try and check the linked article and cant get there I am left wondering if it was Slashdotted or if someone crashed the servers using the exploit.
Hell, who knows, maybe this one is Google's fault too.
Fwiw, I wouldn't go into riot mode over four monosyllable words taken out of context be it from MS or OBSD. Of course, this is /. and that nice little blurb will most certainly cause a lot of banner hits as people will just have to comment. I can personally attest to 3 to get this post up.
I don't want knowledge. I want certainty. - Law, David Bowie
I'd find the OpenBSD crew's haughty "more secure than thou" attitude a lot more annoying if it weren't for the fact that their track record actually justifies it. The fact that you can still count the number of remote exploits using a two-bit register is pretty impressive.
now, how many times does this happens to your favorite OS vendor and their favorite web browser???
from the openbsd CVS:
Revision 1.82 / (download) - annotate - [selected], Wed Feb 4 08:47:41 2004 UTC (38 hours, 50 minutes ago) by itojun
Branch: MAIN
CVS Tags: HEAD
Changes since 1.81: +100 -18 lines
Diff to previous 1.81 (colored)
strictly follow RFC2460 section 5, last paragraph (sender behavior when path MTU 1280). bug found by Georgi Guninski. ok dhartmei
The day Microsoft has half the kind of security track record as OpenBSD, they'll be cut some slack.
OpenBSD had earned a little slack. MS still has a long way to go in system security/stability before they deserve the same treatment.
What crackpipe have you been using? It must greatly enhance the smoking experience. The funding was not pulled "pulled moments before it was to be paid," the funds were already greatly used. There was about three months left before the funding from POSSE was ended. Theo does not seem like an ass to me, he does instead seem like someone that dismisses stupid shit that random people say because he has better things to do.
I'm sick of following my dreams - I'm just going to ask them where they're going and hook up with them later.
A "remote hole" doesn't have to just be obtaining root access. Being able to remotely crash a server is almost as bad. So no, they cannot boast.