đ¨NTP
âšī¸ Introduction
NTP is the longest running, continuously operating, and a distributed application on the Internet. The objective of NTP is simple: to allow a client to synchronize its clock with UTC (Coordinated Universal Time, standard time scale used by most nations), and to do so with a high degree of accuracy and a high degree of stability.
NTP (currently version 4) is a combination of thr ee things; first it is a software program that runs in t he background of Windows/UNIX secondly it is a protocol th at exchanges time that is been valued between servers and cl ients and finally it is a suite of algorithms that process the time values to advance or retreat the system clock. The term NTP applies to both the protocols and the client-server programs that keep running on PCs. NTP time servers work inside the TCP/IP suite and depend on User Datagram Protocol (UDP) port 123. NTP servers are ordinarily committed NTP devices that utilize a single time reference to which they can synchronize a system.
How NTP works?
NTP timestamps are stored as seconds since January 1, 1900. 32 bits for the number of seconds, and 32 bits for the fractions of a second.
NTP assumes that the time spent on the network is the same for sending and receiving.
âī¸ Checklist
Enumeration
Through NTP enumeration you can gather information such as lists of hosts connected to NTP server, IP addresses, system names, and OS running on the client system in a network. All this information can be enumerated by querying NTP server.
nmap
The ntp-info script can extract the remote system's timestamp against the first host and a great deal of information about the second host including kernel version and ntpd version.
As expected, a misconfigured NTP server reveals version and system details among other information which can be used to search for exploits against the vulnerable host.
This can be automated by using a Metasploit auxiliary module
metasploit modules
This module identifies NTP servers which permit the above mentioned "monlist" queries and obtains the recent client's list. The monlist feature allows remote attackers to cause a denial of service (traf fic amplification) via spoofed requests. The more clients there ar e in the record, the higher the amplification
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