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Show HN: Coldframe, a honeypot that poses as a supermarket fridge controller

https://github.com/hedgerow-dev/coldframe

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!

( 67 comments | 3 points | on HN )
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by xrd on Saturday November 07, 2026 @12:41PM (#50406412)
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?

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by eterm on Saturday November 07, 2026 @01:02PM (#50406565)
There have been (at least) two separate waves to this now, which makes the "innocent broken update" speculation much less likely?
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by msephton on Saturday November 07, 2026 @05:19PM (#50408600)
Unless they push updates in waves, which is what most big rollouts do.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by Bengalilol on Saturday November 07, 2026 @01:02PM (#50406566)
Now, as of November 2026, it is confirmed as a hack.

Confirmed exploits, many manufacturers, experts, …

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @01:24PM (#50406745)
My view is that some companies installing this have not implemented any defense in depth and cut corners all around. Installing a firewall with a simple vpn service would probably have prevented lots of pain (unfrosting). In general we also see almost every security expert working at banks or other high paying companies and not for supermarkets. My feeling is that this 'niche' is probably interesting to spend some 'tokens' and time on.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by raizer88 on Saturday November 07, 2026 @01:05PM (#50406605)
This type of attack lasted few days in different countries, quite hard to believe the fridge manufacturer could keep pushing these updates after all the news around.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by embedding-shape on Saturday November 07, 2026 @01:23PM (#50406736)
> Is there a definitive story that someone actually did hack these units on a grand scale?

Given the scope here (see map at https://en.wikipedia.org/wiki/2026_French_supermarket_refrig...), it'd either be individual hackers getting inspired from their neighbor hackers, or one actor targeting European countries.

Although seemingly the hack wasn't so sophisticated, maybe it's truly just some kids fucking around with what they see being open, and maybe just want to target European countries for the "lulz" or whatever, who knows.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @01:27PM (#50406764)
It's most certainly a form or hybrid warfare. While being very easy to perform, it's still quite effective. Empty supermarkets and supply chains being disturbed. Hopefully this is a wakeup call for the industry.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by noir_lord on Saturday November 07, 2026 @01:40PM (#50406849)
> Hopefully this is a wakeup call for the industry.

Would be nice but none of the other <waves at cybersecurity for the last decade> events has been.

It seems like something horrific is going to have to happen before this is taken as seriously by government and private orgs as it should have been, that seems to be how it works with other stuff historically.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by jknoepfler on Saturday November 07, 2026 @01:40PM (#50406857)
Fwiw, the first thread I recall was a speculative blog post about commissary freezers for the US military: https://news.ycombinator.com/item?id=49508506
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by wiml on Saturday November 07, 2026 @10:39PM (#50410232)
That's the first of four incidents I've seen in the news recently. As far as I know it's the one that could have been some other kind of correlated failure (bad update, calendar bug, whatever). We don't know much about it.

After that were two separate supermarket events, which I think were both linked to the known Danfoss vulnerability (CVE-2025-41450); and most recently a blood bank event.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by Muromec on Saturday November 07, 2026 @03:11PM (#50407607)
That's a known playbook. Stir up shit, then create an uplausible denial which will take experts some time to debunk. Once it's figured out the story was bs, put out another three. By the week end there is 10 narratives and nobody except the field experts is sure that it's the usual suspects doing the usual things, but nobody listens to those
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by gruez on Saturday November 07, 2026 @09:23PM (#50409930)
Examples of this happening in the past?
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by Muromec on Sunday November 08, 2026 @07:30AM (#50412698)
I believe the most documented example is mh17
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by supriyo-biswas on Saturday November 07, 2026 @01:03PM (#50406579)
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; 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.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @01:21PM (#50406723)
At this point the honeypot I'm running is not marked as honeypot. Guess that it's a good sign?
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by supriyo-biswas on Saturday November 07, 2026 @01:28PM (#50406770)
What I meant is that I'd find some way of ensuring that I'd want to ensure that the responses you're serving up are real. If you are happy with what you have, we're good.
[dead]
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by direwolf20 on Sunday November 08, 2026 @12:59AM (#50410799)
Did AI write this comment?
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by Shorel on Sunday November 08, 2026 @01:11AM (#50410852)
The tell is the biggest tell. xD
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by ThePowerOfFuet on Sunday November 08, 2026 @03:11AM (#50411338)
Danfoss was misspelled, so probably not.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by jdiff on Sunday November 08, 2026 @05:42PM (#50418264)
The comment, and the Show HN post.

> 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.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by IshKebab on Saturday November 07, 2026 @01:05PM (#50406598)
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.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @01:25PM (#50406755)
I agree, I rushed this one a bit. Glad to share with the industry at least.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by realty_geek on Saturday November 07, 2026 @02:42PM (#50407391)
TBH, I think at this point it is the "holier than thou" people pointing out every instance of slightly AI sounding text that are getting annoying.

I was happy reading you post and I imagine there are many many more people like me than the grinch.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @02:48PM (#50407435)
Thanks! To be honest, using AI helps 'gettings things out' instead of shelving it because it's never perfect.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by phyzome on Sunday November 08, 2026 @12:27AM (#50410655)
While it might help you get things out faster, it's still counter to this one fundamental rule:

If you couldn't be bothered to write it, I can't be bothered to read it.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by realty_geek on Sunday November 08, 2026 @05:01AM (#50411851)
I have met super intelligent people who speak multiple languages but need a bit of help writing stuff in English.

I have no idea who you are, but I would rather give you the benefit of the doubt then try to get a dopamine hit by attacking you.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by IshKebab on Saturday November 07, 2026 @04:01PM (#50408018)
> I think at this point it is the "holier than thou" people pointing out every instance of slightly AI sounding text that are getting annoying.

I don't think it's unreasonable to spend literally 3 minutes writing your own submission. I'm not asking to rewrite every code comment.

And it wasn't "slightly" AI sounding text. It's very obviously AI.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by uptrails on Saturday November 07, 2026 @01:40PM (#50406853)
> 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.

How many information security or IT people do you imagine a typical European grocery store employs?

That's the thing: we build IoT technology that requires constant unobvious maintenance, and we then sell it to people who can't possibly do this kind of maintenance. This is on us, not them.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by morkalork on Saturday November 07, 2026 @01:54PM (#50406970)
Crazy thing is, when the fridges in all those military bases were hacked people were initially in denial and the people noticing that it was just a little too coincidental to be happing simultaneously were called paranoid. Well who's paranoid now?
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @01:51PM (#50406941)
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.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by amenghra on Saturday November 07, 2026 @03:35PM (#50407811)
This is how it should work: supermarket wants to use high tech stuff such as connected fridges, they get a cyber insurance policy as part of all the other insurances they have. The insurer then has domain experts to figure out what the insured needs to do to meet a risk threshold (or they adjust fees accordingly).

This model has worked fine for many other types of risks.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @03:41PM (#50407851)
Many of these supermarkets are part of big brands but operate independently. I doubt cyber insurance is top of mind for those small owners
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by SoftTalker on Saturday November 07, 2026 @04:29PM (#50408245)
It will be soon. How many refrigerated cases of product can they afford to lose?
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by gruez on Saturday November 07, 2026 @09:22PM (#50409927)
Not to mention other ways cyberattacks can paralyze their business, eg. their POS system
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by rcxdude on Sunday November 08, 2026 @04:51AM (#50411806)
In practice this insurance (which already exists!) just creates another compliance checklist and not a meaningful focus on actual security.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by _kb on Saturday November 07, 2026 @10:02PM (#50410070)
That seems pretty location dependant. In Australia at least the two major supermarket chains are not insignificant (e.g. EBITDA ~$5 billion and ~$2.6 billion) and have large internal tech and cyber teams.

I think this is more indicative of the plethora of technical debt and straight up technical negligence that's accompanied the past 10-15 years of internet connected everything. What's happening today is the predictable result of project based works funded by capex deploying assets (of all types) with no consideration of opex funding for the technology components.

Just because a webserver is running in some physical device (fridge, camera, vacuum, washing machine, pump controller, lighting system, audiovisual equipment, access control system etc) does not magically exempt it from the same sort of ongoing sysadmin and maintenance you'd expect as a baseline for something running on standard compute. That applies equally to manufacturers publishing firmware, and the asset owners/service companies that have the responsibility to apply.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by gspr on Sunday November 08, 2026 @04:17AM (#50411629)
Agree with all of what you're saying, wholeheartedly.

But I keep coming back to: why do supermarkets need networked freezers anyway? Most supermarkets are open most days, with long hours. Can't any adjustments just be done manually by staff on the rare occasions when that is needed? I've seen some people argue that the major usecase is defrosting. But when you're defrosting, you certainly have lots of people on site engaged in emptying the fridge in question. Surely flipping the thermostat is a rounding error as far as costs go?

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by minusLik on Sunday November 08, 2026 @10:09AM (#50413947)
Networking freezers is good for: * continuous monitoring and logging of the freezer's temperature (supermarkets are obliged to do so) * sending alerts when something's off

Regarding the defrosting: Commercial freezers can defrost while the groceries stay in, just like the "No-Frost" freezer at home.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by Shadowmist on Sunday November 08, 2026 @10:59AM (#50414345)
Monitoring/logging/alerting can all be done without storing the network connected computer up to anything that can change the temperature settings. It can and should be a completely separate system.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by _kb on Sunday November 08, 2026 @05:37PM (#50418190)
Also, networked != internet reachable.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by yojo on Sunday November 08, 2026 @01:04AM (#50410825)
I work at a company that sells security software to a major grocery chain. They definitely have a security team, I’ve talked to them.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @01:52PM (#50406950)
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...
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by unglaublich on Saturday November 07, 2026 @01:57PM (#50407002)
Why would it, scarcity generally motivates
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by tough on Saturday November 07, 2026 @02:45PM (#50407415)
One could say blood is a fluid market that responds well to offer and demand
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by zahlman on Sunday November 08, 2026 @12:28AM (#50410664)
> fluid market

Heh.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by throwup238 on Saturday November 07, 2026 @05:55PM (#50408817)
Plot twist: the hackers are members of the Van Helsing Society and the supermarkets were just a trial run in their war against the International Vampire Cabal.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by morkalork on Saturday November 07, 2026 @01:53PM (#50406961)
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.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @01:57PM (#50406995)
New ideas are popping up. I started with fridges because of the recent attacks, but the code makes it easy to add personas. Electric car charing stations and coffee machines were my initial idea, but HVAC and building controllers are probably better ideas. Thanks!
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by Insimwytim on Saturday November 07, 2026 @01:55PM (#50406971)
I misread the title again...

I read it as "Cloudflare, a honeypot that poses as..."

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by vkaku on Saturday November 07, 2026 @02:30PM (#50407273)
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. :)

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @02:33PM (#50407305)
Agreed, that's the real fix. The honeypot is just to see who's looking while they're still out there.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by viraptor on Sunday November 08, 2026 @04:24AM (#50411662)
Honeypots are not there to prevent or disrupt attacks. You use them to collect interesting interaction samples. The author is not running any real fridges or making any choices any protecting them.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by DANmode on Saturday November 07, 2026 @03:27PM (#50407751)
Super cool, especially showing your work as FOSS, but: why announce your honeypot before it’s fulfilled its intended purpose once?
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Saturday November 07, 2026 @03:34PM (#50407801)
The more people that can deploy it, the higher the chance of discovering something about the attacks. Also this gave me an incentive to look deeper into the real software.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by gukov on Saturday November 07, 2026 @05:50PM (#50408781)
Not a headline I ever expected to read. 2026 has been a wild year.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by Crunchified on Saturday November 07, 2026 @06:46PM (#50409138)
It's been a wild year from a suburbanite perspective. There's still a long way to go before real wilderness is witnessed.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by amelius on Saturday November 07, 2026 @06:03PM (#50408895)
The interesting part of these attacks was that they seemed to be done per country.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by asdf88990 on Saturday November 07, 2026 @07:05PM (#50409254)
Did you write this post with AI?

- 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.

Given the context, this reads like vomit.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by grey-area on Sunday November 08, 2026 @01:40AM (#50410965)
Of course they did. That text is Claude.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by viraptor on Sunday November 08, 2026 @04:22AM (#50411653)
Both the post and the comments. It's cringe. Just write what you have to write, author.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by Melatonic on Saturday November 07, 2026 @08:29PM (#50409717)
[delayed]
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by throwaway2037 on Sunday November 08, 2026 @01:45AM (#50410989)
Did anyone else notice the badge at the top of the GitHub README.md?

    > HackerNews: #1 Repo of the Day - 214 points
Here is the link from the README.md:

    <img src="https://hackergit.org/badge/hedgerow-dev/coldframe.svg?style=rank&rank=day" alt="Hacker News" width="250" height="55">
Something about it is cringe to me. It is giving LinkedIn self-promotion vibes.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by saidnooneever on Sunday November 08, 2026 @03:03AM (#50411298)
i think it would be pretty trivial to determine the box is a pot from whois etc.

people who target these supermarket chains etc. are doing just that. not scanning the entire internet and popping all the fridges, but doing targeted attacks.

mostly your pot will just be a +1 on benign peoples scanners.

you want honeypots for things that are mass exploited, not for things used in targeted attacks.

just my 2 cents. respect the project can be fun to do ofc but i wouldnt expect much interesting results.

Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by hedgerow-dev on Sunday November 08, 2026 @03:33AM (#50411436)
Great input, thanks! My next step is to deploy on a normal ISP and not on a cloud provider. Just let it sit there. I think we should give back to those companies as much as possible. OT is not where the big money is and all security experts are flocking to. I've already started some actions in this direction btw.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by asjo on Sunday November 08, 2026 @06:30AM (#50412348)
Can't open the link, GitHub is down:

    503 Service Unavailable
    No server is available to handle this request.
Re:Show HN: Coldframe, a honeypot that poses as a supermarke... by mathfailure on Sunday November 08, 2026 @09:49AM (#50413817)
Why?