Tell HN: Cloudflare silently injects its analytics when you switch nameservers
A few hours ago I switched my nameservers to Cloudflare in order to enable R2 bucket serving through my own subdomain, and I found out that it silently had injected a JS analytics snippet in my HTML-only JS-free site textlog.cc — I had to go to the Analytics dashboard, Add the site to the analytics and then disable the snippet. I find this approach entirely invasive, you should opt-in to features like that not have to opt-out. Just a warning out there to folks who might not be aware of this.
An alternative: <meta http-equiv="Content-Security-Policy" content="script-src 'self' https://only-scripts-allowed-from-here.com">
This makes the client only load self-hosted scripts, or scripts only from the specified origins, among the other directives CSP allows (e.g. restricting styles, images, frames, etc.): https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/CSP
If Cloudflare (CF) has r/w access to the response body, which CF does have by default, then CF can easily modify or remove that <meta> tag
Third parties injecting scripts, etc., e.g., analytics, advertising, etc., into response bodies (web pages) is usually cited as a rationale for using HTTPS^1
CF somehow avoids the usual objections. CF is a MiTM but few people object
1. For example, a data collection, surveillance and advertising services company that operates a www search engine and releases a web browser may not want an ISP to inject scripts, etc., e.g., analytics, ads, etc., into web pages as it might compete with the company's business. As a defense against such ISPs and other third parties that are potential competitors for data collection/surveillance/advertising services, it might favor HTTPS sites in its www search engine results, promote HTTPS at conferences discussing its web browser, etc.
Thanks for the background context, very interesting and realistic. Yes, of course it also has read/write access, though I always make sure there’s no interference of that kind. It has only happened to me once, where a binary I hosted on Pages didn't work when downloaded with wget (though that happened several years ago).
Also can add "Cache-Control: no-transform" header, which prevents modifying the payload.
Yikes! I see this too:
<script type="module" src="https://static.cloudflareinsights.com/beacon.min.js/v4513226..." integrity="sha512-ZE9pZaUXND66v380QUtch/5sE9tPFh2zg45pR2PB0CVkCtOREv2AJKkSidISWkysEuQ0EH8faUU5du78bx87UQ==" data-cf-beacon='{"version":"2024.11.0","token":"c0859b51a7804ab5a9cc8e9e2b2c4cde","r":1}' crossorigin="anonymous"></script>
Yup, I explicitly had all anaytics turned off. But had a few sites using Cloudflare for caching. Now I'm checking and seeing this on all of them. This is gross and unacceptable. "Caching" does not mean "modifying my site".
I'm not seeing this on my site (if you want to check: https://stackgho.st), are you using their `strict` http settings? I.e. is your server terminating TLS or is theirs?
edit: perhaps it's only for sites added after that policy came into effect
Indeed, https://blog.cloudflare.com/the-rum-diaries-enabling-web-ana...
Perhaps it drowned in newslop when announced?
The RUM Diaries: Enabling Web Analytics by Default
(2 points, 11 months ago): https://news.ycombinator.com/item?id=45291323
(1 point, 11 months ago): https://news.ycombinator.com/item?id=45339321
If you're only using Cloudfare for DNS, but HTTPS connections go directly to your server, how does it inject HTML?
You must be allowing Cloudfare to terminate your HTTPS connections; i.e. using them for actual proxying.
The orange cloud icon in dns settings, in other words, but that's opt-out too. So yeah - double opt-out I guess.
I have no idea what 'the orange cloud icon' means, as I'm not a CloudFlare used.
But DNS/Name servers do not see HTML traffic, as the above poster mentioned, so it's not obvious how this change would matter.
Is it that they are serving their HTML via CloudFlare, and cloudflare is making changing in its serving of their html?
Are you using CF as a proxy or only for DNS? I ask because I just went to check my domains on the dashboard (some purchased a few years ago, one purchased just a couple days ago), and none of them have Web Analytics enabled.
I have all my domains set to DNS only, so no CF proxy. Wondering if that is why?
I just went and switched them to DNS only, they were on Proxy by default, that also should have been opt-in. Maybe I missed the option while switching the nameservers because I did it in a hurry but still.
> that also should have been opt-in.
The proxy is like 99% of why people use Cloudflare
A simple screen when I did the switch that requires explicitly ‘Enable Proxy’ or ‘skip for now’ would have been enough. Also for ‘Enable Analytics’. None of these existed, or not very obvious otherwise I’d seen them.
I agree it is a bit confusing, but it makes sense if you think about the expected default use case, which is enabling the cloudflare CDN for customers. They expect people to be using their CDN.
I use them for my registrar, because they offer domains at cost and you can’t beat that. But yes, they make it an extra step to use them without using the CDN.
Once you figure it out, it is fairly straightforward, though, and you can’t beat the price.
This reminds me of the old free hosts that would inject their own scripts/ads on pages hosted by them, but their implementation would do it only after detecting the closing HTML tag (either </body> or </html>, can't remember) and the various tricks to get around it, including omitting the tag (browsers don't care), rAnDoM case tags (some were hardcoding lower or upper and comparing case-sensitively), and messing with the content type and relying on the browser to detect correctly since it didn't inject into other types (not sure how the current browsers will handle that).
I'm getting flashbacks to Proxomitron, a localhost proxy in the HTTP days when it was also much harder/impossible to make browser plugins.
Yes, they add the js if "web analytics" is enabled. I believe I had to manually enable it on my old sites though. Maybe it's enabled by default when adding new domains?
No, I hadn’t enabled for any site. I had to enable first to turn it off.
Maybe send it to them as a bug. Seems more like a mistake than malevolence.
Isn't this well known when using CF as a proxy? Not sure how they would provide traffic / DDoS telemetry otherwise.
They're serving the HTML, they have every ability to track individual web requests without modifying the content they're serving.
100% But this does not give you any useful personal data :)
Or data for the increasingly invasive Cloudflare captcha.
Took me a minute to realise this isn't 1.1.1.1 (which Cloudflare also runs), but their original website DNS hosting service.
What else would you expect from Cloudflare?
It this point in time it is somewhere between GoDaddy and RyanAir in dark pattern usage
I noticed the same thing with email-decode.min.js on my site. It turns out it's the "Email Address Obfuscation" feature, which I didn't expect to be on by default.
Is there an opt-out mechanism at least? CF is burning goodwill in months it built over the last decade.
Yes there is. I have it disabled on mine:
https://limereader.com/
Thank you for this. I indeed had it up on mine. Cloudflare has switched defaults a couple times now, which honestly is wild to me.
yep, last website I did was JS free 100% except that pesky cloudflare script
> injected a JS analytics snippet in my HTML-only JS-free site textlog.cc
Cloudflare injected hostile code into a site they are not even hosting? If it's HTTPS, how do they even do that?
Does it violate the "exceeds authorized access" provision in the Computer Fraud and Abuse Act?
The most likely answer is the person accidentally enabled the cloudflare reverse proxy without understanding what they were doing.
It seems incredibly unlikely cloudflare does this when just DNS hosting, if for no other reason then that this would break so many things.
I can’t recall if there was a setting to enable reverse proxy, if there was it was On by default since I didn’t expect to have reverse proxy enabled as well. But you can also rp without injecting a script. That’s overdoing it.
If the cloud symbol is orange, it's enabled. I believe they'll even warn you if you disable it, a lot of people enable it unintentionally.
I don't know what happened in this situation but beware that CF and similar providers are not true DNS hosting providers. They do DNS, but only so their CDN stuff works, and to lock their customers from using whatever DNS hosting they want. Various things that one might reasonably want to do with your DNS zone are not possible with their product. So use it only because you need to do so in conjunction with their core services.
If this is HTTPS, how would Cloudfare have the certificate for your domain so that browsers don't warn about a mismatch?
Or is it that when you sign over DNS to a provider, they can take over your cert? They can "ass-cert" their own? :)
As far as I know they terminate all TLS; it’s one of the tradeoffs using them.
They have a product called Magic Transit that offers DDoS protection and such for plain IP traffic, where Cloudflare does not terminate TLS. Pricing is not public but starts in the five-digit USD per month range according to people I talk to.
This may tell you something about how keen Cloudflare are to handle traffic they themselves cannot decrypt.
Magic Transit uses BGP magic to work. That only makes sense at scale - i believe you have to have your own ASN for it to work.
Realistically its a totally different product, and 5 digit price is probably cheap relative to competitors in that space.
Yes, the person who controls the DNS controls the certificate.
What a certificate is supposed to verify is that traffic is going to the right place. If you designate cloudflare as the rightful host of your website then they can get a certificate.
This isn't an edge case though. This is cloudflare's primary product. It is why users use them.
When you set up CNAME and certain other records in Cloudflare DNS, it defaults to (and heavily discourages you to disable) "proxied" records, which I believe means that the record points to a Cloudflare-owned host which then acts as a reverse proxy to whatever value you'd set. So from the console it looks like you've set the CNAME to a certain value, but in practice it'll be set to a different thing and transparently forward everything via Cloudflare. This is probably where the analytics get inserted, alongside a bunch of other Cloudflare features.
You can disable this, at which point the record will be set as a normal DNS record.
I can see the advantage of Cloudflare's proxy systems, but I wish they'd be clearer about when they're being used and not pretend that this is some DNS feature or that records have been set to one thing when they've actually been set to something else. If nothing else, it makes debugging DNS issues a lot more confusing, particularly if you're not a DNS expert.
>I can see the advantage of Cloudflare's proxy systems, but I wish they'd be clearer about when they're being used and not pretend that this is some DNS feature or that records have been set to one thing when they've actually been set to something else. If nothing else, it makes debugging DNS issues a lot more confusing, particularly if you're not a DNS expert.
You could say the same about the reverse, ie. people set up their site on cloudflare, thought it was "protected", but really it's dns only and their servers are wide open. It's even worse if they migrated from another provider that was providing ddos protection.
On the other hand. Proxying websites (for ddos protection, cdn, etc) is their primary product. Its what they are known for.
I think a better question is: why would you be using cloudflare, if you didn't want that?
> It seems incredibly unlikely cloudflare does this when just DNS hosting
Not to mention impossible when ‘just’ DNS hosting. Though I suppose they could secretly replace the stated IP with one of their own anyway and then still proxy the content.
TLS terminates at Cloudflare, not at your origin. When a record is proxied (the orange cloud), CF holds the certificate the browser validates against and opens a separate connection to your server, so it sees plaintext on both sides and can rewrite the HTML on the way out. Same mechanism that makes the WAF and caching work, so it isn't specific to the analytics feature.
Worth checking which of your records are actually proxied. DNS-only ones (grey cloud) pass straight through and can't be touched.
It's not necessary to use Cloudflare hosted DNS to use R2 with a custom subdomain.
Make a CNAME record the same way you would for a CDN subdomain.
(I am not yet running this in production, YMMV.)
Then you don't get edge cache though, right? And maybe some other features?
We use Cloudflare tunnels for connecting distributed workers to central infrastructure. Haven't seen this on tunnel traffic, but good to know it happens on nameserver-managed sites. Another reason to audit what your CDN injects — same applies to checking your security headers regularly.
You left out the part about how you use them as a reverse proxy, which is decoupled from DNS. One is coincidental; the other required.
If they can inject script, they can also snoop on all your cleartext traffic without you knowing....
Indeed. I have several domains using cf for dns only and they don't/can't inject anything into those sites.
"can't" is incorrect. As your name server, they can decide to turn the reverse proxy/caching at any point in the future, write an obscure blog post about how this is the best solution for all (a post that gets 2 comments on HN due to other news that week), and you'd only find out about it 11 months later in a thread like this one.
Oh gosh I didn’t enable anything like that also. I just wanted the nameservers in order to serve the bucket under my subdomain. What else is there I wonder?
Ok to turn this off you go Domains → Overview → your.site → DNS → Records → then Edit each entry to DNS Only (gray cloud). MITM gone now (I hope).
OK, how can Cloudfare edit your HTML without it passing through your server?
If the browser connects directly to your web server, how can there be Cloudfare's analytics stuff?
Check what IP address you are connecting to when you load textlog.cc. Is that an address that you control? If it's not an address that you control, where is it getting your page, and is that not called proxying?
The main reason anyone chooses cloudflare is for their CDN (which I suppose is a "reverse proxy"...not a way I'd refer to it but technically yes that's essentially what it's doing). If you don't need the CDN or any of the other fancy features there are plenty of straight DNS providers out there (and often provided by the registar these days).
To add to your experience: It was also very hard, for me, to find the setting that disables this JavaScript.
cloudflare is malware, what did you expect?
A public service reminder to anyone setting up their domains that there are many alternatives to Cloudflare, like EG Bunny.net (I am not affiliated, just a happy customer) and that by using one of these other DNS providers, you
- play your small part in keeping the Internet open
- delay or avoid entirely the enshittification that is 100% foreseeable when buying the "free" services of a quasi-monopoly vendor.
If you're not an enterprise customer, alternate providers will also give you every single feature you could ever need and more, and fewer surprises like the OP's.
Spies. Spies everywhere
Noticed this the other day as well. Sketchy as fuck. I didn't have analytics enabled. I had to go and enable to get access to the option to turn this off
Surprise! The man in the middle man-in-the-middles! This is only the beginning, when you’ll get used to this they’ll do worse and worse, enshittification, remember?
If I wouldn't know it better I'd sometimes think some of the big tech shops are just fronts for centralizing the net.
Cloudflare is doing this already. Once they had enough monopoly power, they started a program to block all bots that don't undergo invasive KYC procedures. Eventually, they might become a KYC broker for regular browser users too. The free internet is over.
#savetheinternet
I don't know what would give anyone that idea. [1]
[1] - https://www.youtube.com/watch?v=a3Xxi0b9trY
That's exactly what they are.
And they can fuck off.