Last updated at Fri, 15 Dec 2023 14:54:18 GMT

In early 2015, HD Moore performed one of the first publicly accessible research related to Internet-connected gas station tank gauges, The Internet of Gas Station Tank Gauges.

Later that same year, I did a follow-up study that probed a little deeper in The Internet of Gas Station Tank Gauges — Take #2. As part of that study, we were attempting to see if the exposure of these devices changed in the ~10 months since our initial study as well as probe a little bit deeper to see if there were affected devices that we missed in the initial study due to the study's primitive inspection capabilities at the time. Somewhat unsurprisingly, the answer was no, things hadn't really changed, and even with the additional inspection capabilities we didn't see a wild swing that would be any cause for alarm.

Recently, we decided to blow the dust off this study and re-run it for old-time's sake in the event that things had taken a wild swing in either direction or if other interesting patterns could be derived.  Again, we found very little changed.

Not-ATGs and the Signal to Noise Ratio

What is often overlooked in studies like this is the signal to noise ratio seen in the results, the "signal" being protocol responses you expect to see and the "noise" being responses that are a bit unexpected.  For example, finding SSH servers running on HTTP ports, typically TCP-only services being crudely crammed over UDP, and gobs of unknown, intriguing responses that will keep researchers busy chasing down explanations for years.

These ATG studies were no exception.

In most recent zmap TCP SYN scan done against port 10001 on November 3, 2016, we found nearly 3.4 million endpoints responding as open. Of those, we had difficulty sending our ATG-specific probes to over 2.8 million endpoints — some encountered socket level errors, others simply received no responses. It is likely that a large portion of these responses, or lack thereof, are due to devices such as tar-pits, IDS/IPS, etc. The majority of the remaining endpoints appear to be a smattering of HTTP, FTP, SSH and other common services run on odd ports for one reason or another.  And last but not least are a measly couple of thousand ATGs.

I hope to explore the signal and noise related problems related to Internet Scanning in a future post.

Future ATG Research and Scan Data

We believe that is important to be transparent with as much of our research as possible.  Even if a particular research path we take ends up a dead, boring end, by publishing our process and what we did (or didn't) find might help a future wayward researcher who ends up in this particular neck of research navigate accordingly.

With that said, this is likely to be our last post related to ATGs unless new research/ideas arise or interesting swings in results occur in future studies. Is there more to be done here?  Absolutely!  Possible areas for future research include:

  • Are there additional commands that exposed ATGs might support that provide data that is worth researching, for security or otherwise?
  • Are there other services exposed on these ATGs?  What are the security implications?
  • Are there advancements to be made on the offensive or defensive side relating to ATGs and related technologies?

We have published the raw zmap TCP scan results for all of the ATG studies we've done to date.  We have also started conducting these studies on a monthly basis and these runs will automatically upload to when complete.

As usual, thanks for reading, and we welcome your feedback, comments, criticisms, ideas or collaboration requests here as a comment or by reaching out to us at