ntpd vulnerabilities

[Dag-Erling Smørgrav]

Joe Malcolm <jmalcolm at uraeus.com> writes:
> Dag-Erling Smørgrav <des at 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
-- 
Dag-Erling Smørgrav - des at des.no