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NTP "NAK to the Future"

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NTP "NAK to the Future"



Crypto-NAK packets can be used to cause ntpd to accept time from unauthenticated ephemeral symmetric peers by bypassing the authentication required to mobilize peer associations. This module sends these Crypto-NAK packets in order to establish an association between the target ntpd instance and the attacking client. The end goal is to cause ntpd to declare the legitimate peers "false tickers" and choose the attacking clients as the preferred peers, allowing these peers to control time.


  • Matthew Van Gundy of Cisco ASIG
  • Jon Hart <jon_hart@rapid7.com>


Module Options

To display the available options, load the module within the Metasploit console and run the commands 'show options' or 'show advanced':

msf > use auxiliary/scanner/ntp/ntp_nak_to_the_future
msf auxiliary(ntp_nak_to_the_future) > show actions
msf auxiliary(ntp_nak_to_the_future) > set ACTION < action-name >
msf auxiliary(ntp_nak_to_the_future) > show options
    ...show and set options...
msf auxiliary(ntp_nak_to_the_future) > run 

Time is precious, so I don’t want to do something manually that I can automate. Leveraging the Metasploit Framework when automating any task keeps us from having to re-create the wheel as we can use the existing libraries and focus our efforts where it matters.

– Jim O’Gorman | President, Offensive Security