The Shadowserver Foundation

Open NTP Monitor (Mode 7) Scanning Project

If you are looking at this page, then more than likely, you noticed a scan coming from this server across your network and/or poking at NTP.

The Shadowserver Foundation is currently undertaking a project to search for publicly accessible devices that have NTP running and answering Mode 7 queries for MON_GET_LIST. The goal of this project is to identify openly accessible NTP services and report them back to the network owners for remediation.

These devices have the potential to be used in NTP amplification attacks and if at all possible, we would like to see these services made un-available to miscreants that would misuse these resources.

Servers that are configured this way have been incorporated into our reports and are being reported on a daily basis.

Information on UDP-based amplification attacks in general can be found in US-CERT alert TA14-017A at: https://www.us-cert.gov/ncas/alerts/TA14-017A

Methodology

We are querying all computers with routable IPv4 addresses that are not firewalled from the internet on port 123/udp with an NTPv2 request for the MON_GETLIST_1 control message. We are capturing the response from the NTP service and parsing the result. We intend no harm, but if we are causing problems, please contact us at gro [tod] revfooreswodahs [ta] nacbarssnd

If you would like to test your own device to see if it supports Mode 7 queries, try the command: "ntpdc -n -c monlist [IP]". If the command is successful, you will see a table of data returned that starts with these headings: "remote address port local address count m ver rstr avgint lstint"

Whitelisting

To be removed from this set of scanning you will need to send an email to dnsscan [at] shadowserver [dot] org with the specific CIDR's that you would like to have removed. You will have to be the verifiable owner of these CIDR's and be able to prove that fact. Any address space that is whitelisted will be publicly available here: https://ntpmonitorscan.shadowserver.org/exclude.html

Useful Links

Scan Status

Statistics on current run

Other Statistics

If you would like other statistics and information on historical trends, please take a look at: https://ntpmonitorscan.shadowserver.org/stats/. Otherwise, stats from the most current scan are listed below.


All NTP Monitor (Mode 7) Servers

All NTP (Mode 6)

(Click image to enlarge)

These are the approximatly 100,000 open NTP servers

If you would like to see more regions click here

All NTP Monitor (Mode 7) Servers

All NTP (Mode 6)

(Click image to enlarge)

These are the approximatly 100,000 open NTP servers



If you would like us to not scan your network, please let us know and we will remove your networks from the scan.

Likewise, if you have anymore questions please feel free to send us an email at: gro [tod] revfooreswodahs [ta] nacbarssnd

The Shadowserver Foundation