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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Joe Malcolm <jmalcolm@uraeus.com>
Subject: Re: ntpd vulnerabilities
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Date: Tue, 23 Dec 2014 14:18:25 +0100
In-Reply-To: <21657.26902.156000.609968@neoshoggoth.uraeus.com> (Joe Malcolm's
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Cc: freebsd-security@freebsd.org, Robert Simmons <rsimmons0@gmail.com>,
 Winfried Neessen <neessen@cleverbridge.com>
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Joe Malcolm <jmalcolm@uraeus.com> writes:
> Dag-Erling Sm=C3=B8rgrav <des@des.no> writes:
> > These work on a "last match" basis.  The latter three lines lift all
> > restrictions for localhost, so you can still "ntpq -pn" your own
> > server, but nobody else can.
> Thanks. So, if I understand correctly, the shipped config is
> vulnerable to local (same-host) attackers, not remote ones.

Broadly, yes.  Restricting requests from localhost makes it impossible
to monitor your own server, because ntpdc and ntpq talk to ntpd over UDP
to localhost rather than a Unix socket, which could be protected by file
permissions.  Implementing a Unix socket for ntpdc / ntpq is left as an
exercise to the reader.

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