alt Hacker NewsShow HN: Coldframe, a honeypot that poses as a supermarket fridge controller
I built Coldframe, a honeypot that pretends to be a supermarket refrigeration controller. Inspired by the events on industrial fridge installations in the past weeks, I wanted to see what people would try against a convincing fake.
To learn more about this I built a honeypot that resembled perfectly the Danfoss AK-SM 800A and Dixell XWEB interfaces. Both of them are recognized on Shodan as real ones (an not as honeypots). It’s one Python file using only the standard library, and it builds on eppser/danfoss-ak-sm-decoy and public research by Synacktiv, Claroty and Ironhackers.
Things that were fun to get right:
- Matching real units. I used Shodan records of real devices to match header order, page titles, certificate fields and TLS versions. The Danfoss persona sends nginx headers in the same order as a real AK-SM 800A. The Dixell persona sends no Server header and pads its page to exactly 8,202 bytes.
- Recognising exploit attempts. It recognises CVE-2025-41450, the Danfoss “code of the day” login bypass, and records whether the submitted code is correct for today. It also tags attempts targeting three other Danfoss CVEs and the XWEB vulnerabilities.
- Letting them in. Default logins open a fake store dashboard with defrost buttons, so you see the second move, not just the first. Nothing behind it is real.
Two instances have been live for a day. So far they’ve only seen generic scanners and Shodan’s crawler, which is called refrigerator.census.shodan.io.
Feedback welcome, especially from anyone who has seen these devices in the field!
Comments
An extra insight, there was some news of 'blood banks' also being targetted. This is possibly a stronger (painful) target. It would demorelize people that are donors. https://www.independent.co.uk/tech/security/blood-hack-fridg...
One thing keeps coming back, (and it's the story of industries where security and patching is an afterthought).
a supermarket has no security team. If a fridge controller needs patching, a VPN and a strong password to be safe, that work has to come from the vendor or installer by default. One would hope that all these come by default or as a feature on these devices. It could even be a selling feature and not part of an expensive maintenance contract. A supermarket manager cannot be expected to do this work.
Super cool, especially showing your work as FOSS, but: why announce your honeypot before it’s fulfilled its intended purpose once?
Wait, I recall reading the threads about someone speculating there was a hack. Some people suggested it could just be that a large percentage of refrigeration units received a software update at the same time which resembled a hack.
Is there a definitive story that someone actually did hack these units on a grand scale?
I have briefly misread the title as "Cloudflare, a honeypot that poses as..."
You'd probably have more luck posing as other industrial hardware like HVAC, lighting, controllers for the kinds of pumps or valves you'd find in chemical plants. That kind of stuff.
Me reading it be like:
MFs be doing everything but pulling those fridges off the Internet. Given the amount of TOR nodes, IP addresses today, Honeypots mean nothing ....
Of course, it's my unpopular opinion. :)
The hilarious thing about this is that there was an initial hack, and then like a month later another one that was equally successful. Who could have possibly seen that coming lol.
> Default logins open a fake store dashboard with defrost buttons, so you see the second move, not just the first.
I think we're past the point where it's reasonable to expect people to not use AI for code, but their prose still sucks balls. You should at least write your submission here yourself, come on.
I would be very skeptical of anyone relying on Shodan data. At one point I was trying to write honeypots myself by replicating wifi cameras, but almost all the ones on the internet I found were honeypots of some sort, and the ones that weren't were already hacked and had their web pages replaced. In retrospect it would have probably been better to get a vulnerable device myself and probe it.
If I were you, I would probably ensure that the fridges you used have residential or commercial (aka non-DC) IP addresses. Maybe Shodan uses this data for their "honeypot" label, my experience was some time ago so no idea though.