Vulnerability in NTP (time synchronization)

A vulnerability has been detected in the ntpd package, which makes it possible to use a working service
to conduct attacks on other servers in order to create an overload in processing UDP traffic.

See the CERT bulletin for details.

Method for determining the vulnerability of the service:
ntpdc IP_server
monlist


If the service is vulnerable, a list of type
ntpdc> monlist remote address port local address count m ver code avgint lstint ===============================================================================

And it is recommended to take URGENT measures.

To fix the vulnerability:
- or update the NTP to version 4.2.7;
- or disable the monlist - add the disable monitor command to the configuration file
- or add the following lines into the configuration file

restrict default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery
restrict 127.0.0.1
restrict -6 ::1
restrict 127.127.1.0