“Boobs check” – Technique to verify if sites behind CDN are hosted in Iran

324 points by defly 2 days ago

https://xcancel.com/hkashfi/status/1995109785679573167

This behavior only works when the reverse proxy or CDN is configured like this:

Proxy/CDN: HTTPS (443) → Origin server: plain HTTP (80)

(example: Cloudflare in Flexible mode)

If the origin server uses any proper TLS configuration, even a self-signed certificate, this method stops working. It only succeeds when the upstream connection to the origin is unsecured.

If you want to test this on a random site without Cloudflare or reverse proxy in general on HTTP: curl http://www.digiboy.ir/boobs.jpg -v

mort96 - 2 days ago

Ah, Cloudflare. The world's most widely deployed encryption remover.
- dhab - 2 days ago
  
  Could someone help me understand. I looked at: https://developers.cloudflare.com/ssl/origin-configuration/s... it seems to support multiple modes.
  I didn't quite get if Automatic TLS (https://developers.cloudflare.com/ssl/origin-configuration/s...) could use plain transfers.
  So:
  * Is it insecure by default or you have to be intentionally insecure?
  * Why would anyone pick the flexible/potentially-insecure option?
  - penteract - 2 days ago
    
    > Why would anyone pick the flexible/potentially-insecure option?
    Because having a connection that's encrypted between a user and Cloudflare, then unencrypted between Cloudflare and your server is often better than unencrypted all the way. Sketchy ISPs could insert/replace ads, and anyone hosting a free wifi hotspot could learn things your users wouldn't want them to know (e.g. their address if they order a delivery).
    Setting up TLS properly on your server is harder than using Cloudflare (disclaimer: I have not used Cloudflare, though I have sorted out a certificate for an https server).
    The problem is that users can't tell if their connection is encrypted all the way to your server. Visiting an https url might lead someone to assume that no-one can eavesdrop on their connection by tapping a cross-ocean cable (TLS can deliver this property). Cloudflare breaks that assumption.
    Cloudflare's marketing on this is deceptive: https://www.cloudflare.com/application-services/products/ssl... says "TLS ensures data passing between users and servers is encrypted". This is true, but the servers it's talking about are Cloudflare's, not the website owner's.
    Going through to "compare plans", the description of "Universal SSL Certificate" says "If you do not currently use SSL, Cloudflare can provide you with SSL capabilities — no configuration required." This could mislead users and server operators into thinking that they are more secure than they actually are. You cannot get the full benefits of TLS without a private key on your web server.
    Despite this, I would guess that Cloudflare's "encryption remover" improves security compared to a world where Cloudflare did not offer this. I might feel differently about this if I knew more about people who interact with traffic between Cloudflare's servers and the servers of Cloudflare's customers.
    
    mort96 - 2 days ago
    
    > Setting up TLS properly on your server is harder than using Cloudflare
    This is probably technically true, but setting up TLS properly on your server is really ridiculously simple.
    
    tracker1 - a day ago
    
    These days, absolutely... I usually use Caddy for reverse proxy chores and it's been a great option to deal with. Traefic hasn't been bad either.
    
    ffsm8 - 2 days ago
    
    ...in 2025
    Let's encrypt and ACME hasn't always been available. Lots of companies also use appliances for the reverse proxy/Ingress.
    If they don't support ACME, it's actually quite the chore to do - at least it was the last time I had to before acme was a thing (which is admittedly over 10 yrs ago)
  - wavesquid - 2 days ago
    
    Historically?
    1. Because TLS certificates were not free
    2. Because firewall was "enough" in most people's minds
    3. Because TLS was the most CPU intensive part of serving a static site
    4. Because some people were using cheap shared hosting providers that upcharged for TLS
  - KomoD - 2 days ago
    
    > * Why would anyone pick the flexible/potentially-insecure option?
    I pick it whenever I don't want to setup HTTPS on my origin but still want HTTPS. Just for projects where I really don't care.
- bawolff - 2 days ago
  
  Is it really that different than AWS? You either trust your service provider or you don't.
  - lmm - 2 days ago
    
    AWS doesn't route requests from their load balancer to your server across the public internet. Cloudflare does.
    
    akdev1l - 2 days ago
    
    You can do that with AWS if you really want to.
    It will cost you a ton.
- p0w3n3d - 2 days ago
  
  EU should simply do the global surveillance quietly on cloudflare, instead of asking all the countries for the law
  </Irony>
- spoiler - 2 days ago
  
  To be fair, Cloudflare is also the reason why most sites even have TLS at all, because it offered free certs (through letsencrypt I think?) in a fairly easy to set up way.
  Certs used to be expensive, and had way more operational overhead and quirks (even setting up ACME/LE)
  - estimator7292 - 2 days ago
    
    Absolutely not, no. That is all thanks to Let's Encrypt.
    
    DoctorOW - 2 days ago
    
    This was true before Let's Encrypt existed, they'd buy massive 500 domain wildcard SSL certs that free users would split.
    
    koakuma-chan - a day ago
    
    Let's Encrypt is unusable for me because they want you to install that certbot thing. I don't know what that is or what it does. I don't want some magical auto update thing. Is it so hard to just make a generate button that gives you cert.pem and pkey.pem? Cloudflare managed to do it.
    
    anticrymactic - 11 hours ago
    
    Let's encrypt supports ACME. Here are hundreds of ways to obtain a certificate:
    https://letsencrypt.org/docs/client-options/#other-client-op...
    
    spoiler - 12 hours ago
    
    Right, DoctorOW correct me; I have limited memory about the state of affairs from a decade ago. They offered free certs for a long time regardless of LE integration
    
    thayne - 2 days ago
    
    Cloudflare has native integration with Let's encrypt, which makes using TLS with a CDN much easier than if you had to acquire the ACME cert and deploy it to the CDN yourself.
    Granted, most CDNs these days have some form of free certicate system, but that wasn't always the case.
  - Bratmon - 2 days ago
    
    People on this website will just type any wild lie. I kinda love it.
    The sky is purple! Charlie Brown had hoes! Cloudflare invented Let's Encrypt! Just say anything you want! We live in a post-truth world- there's no need for anything you say to correspond to any external reality!
    
    spoiler - 12 hours ago
    
    I never said Cloudflare was behind Let's Encrypt… Did I? Probably just a misunderstanding.
    Someone l pointed out I mixed up my timeline a bit because this was over a decade ago, but it turns out CF offered free certs even earlier than LE :)
    So, while i got the details wrong, I still stand behind what I say: most sites on the web even have TLS enabled because CF offers it for free. I'm not talking about the reverse proxy aspect, but from the UA's perspective
    
    tracker1 - a day ago
    
    I'm pretty sure Lincoln said that first...
    
    balamatom - 2 days ago
    
    Congrats! You get it!
    
    ranger_danger - 2 days ago
    
    > this website
    you must be new to the internet...
  - Tostino - 2 days ago
    
    I'm not going to give them credit for the work that Lets Encrypt did.
    
    master_crab - 2 days ago
    
    I agree, Let’s encrypt and ACME played a massive role. But it’s still far easier having Cloudflare handle TLS encryption for you.
    And i say this as someone who uses ACME in certmanager and certbot at home and still prefers the ease with which Cloudflare generates a cert for my domain and terminates TLS for the public side of my cloudflare tunnel.
    
    Tostino - 2 days ago
    
    For my home stuff I just use nginx-proxy-manager and haven't thought about it since I set it up a couple of years ago.
    For work, I used to use certbot directly at my old place. Now I am building my new stuff on k8s, and I have the ingress manage my certs for me (likely using certbot or similar behind the scenes). Both have been extremely low setup effort and no ongoing effort.
    I don't like giving Cloudflare my (or my companies/customers) data in exchange for being able to click a checkbox.
    
    spoiler - 12 hours ago
    
    My bad! I slightly confused my timeline. CF offered free certs long before LE!
    
    TiredOfLife - 2 days ago
    
    Lets Encrypt can proxy my old http only website to show as https? Without access to server configuration? How?
    
    Tostino - 2 days ago
    
    With nginx-proxy-manager which uses Let's Encrypt for certs you can... This isn't the gotcha you think it is.
    
    TiredOfLife - 2 days ago
    
    I don't have access to the server.
    
    Tostino - 2 days ago
    
    It can be run anywhere. You don't need it on the same server. Cloudflare isn't running on the same server either.
    
    TiredOfLife - 2 days ago
    
    Cloudflare is a checkbox.