News: 1741086015

  ARM Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life (Terry Pratchett, Jingo)

Cloudflare's bot bouncer blocks weirdo browsers

(2025/03/04)


Users of some of the less well-known web browsers are getting blocked from accessing multiple sites by Cloudflare's flaky browser-detection routines.

Aside from [1]reporting it on Cloudflare's forum , there appears to be little users can do, and the company doesn't seem to be paying attention.

[2]Cloudflare is one of the giants of [3]content distribution network . As well as providing fast local caches of busy websites, it also attempts to block bot networks and DDoS attacks by detecting and blocking suspicious activity. Among other things, being "suspicious" includes machines that are part of botnets and are running scripts. One way to identify this is by looking at the browser agent and, if it's not from a known browser, blocking it. This is a problem if the list of legitimate browsers is especially short and only includes recent versions of big names such as Chrome (and its many derivatives) and Firefox.

[4]

The problem isn't new, and whatever fixes or updates occasionally resolve it, the relief is only temporary and it keeps recurring. We've found reports of Cloudflare site-blocking difficulties [5]dating back to 2015 and continuing through [6]2022 .

[7]

[8]

In the last year, The Register has received reports of Cloudflare blocking readers [9]in March , again [10]in July 2024 , and earlier this year [11]in January .

Users of recent versions of [12]Pale Moon , [13]Falkon , and [14]SeaMonkey are all affected. Indeed, the [15]Pale Moon release notes for the most recent couple of versions mention that they're attempts to bypass this specific issue, which often manifests as the browser getting trapped in an infinite loop and either becoming unresponsive or crashing. Some users of [16]Firefox 115 ESR have had problems, too. Since this is the latest release in that family for macOS 10.13 and Windows 7, it poses a significant issue. Websites affected include science.org , steamdb.info , convertapi.com , and – ironically enough – community.cloudflare.com .

[17]Cloudflare hopes to rebuild the Web for the AI age – with itself in the middle

[18]What happens when someone subpoenas Cloudflare to unmask a blogger? This...

[19]2024 according to Cloudflare: Global traffic up, Google still king, US churning out bots

[20]Cloudflare broke its logging-as-a-service service, causing customer data loss

According to some in the [21]Hacker News discussion of the problem, something else that can count as suspicious – other than using niche browsers or OSes – is something as simple as asking for a URL unaccompanied by any referrer IDs. To us, that sounds like a user with good security measures that block tracking, but it seems that, to the CDN merchant, this looks like an alert to an action that isn't operated by a human.

Making matters worse, [22]Cloudflare tech support is aimed at its corporate customers, and there seems to be no direct way for non-paying users to report issues other than the community forums. The number of repeated posts suggests to us that the company isn't monitoring these for reports of problems.

[23]

We have asked Cloudflare to comment, and we'll update this story if it gets back to us.

Bootnote

Our thanks to Reg readers Ian West and [24]previous commenter and [25]Certified Fraud Examiner Andy Prough for bringing this to our attention, as well as Pale Moon maintainer "Moonchild." ®

Get our [26]Tech Resources



[1] https://community.cloudflare.com/t/access-denied-to-pale-moon-desktop-browser/764330

[2] https://www.theregister.com/Tag/Cloudflare/

[3] https://www.theregister.com/2015/08/28/content_delivery_networks_why_load_balancing/

[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2Z8cxt9FJjItPH3TcefAC3AAAAMY&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0

[5] https://forum.palemoon.org/viewtopic.php?t=7096

[6] https://community.cloudflare.com/t/browser-integrity-check-broken/381029

[7] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Z8cxt9FJjItPH3TcefAC3AAAAMY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[8] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33Z8cxt9FJjItPH3TcefAC3AAAAMY&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[9] https://forum.palemoon.org/viewtopic.php?f=3&t=30950

[10] https://community.cloudflare.com/t/verify-you-are-human-checks-broken-in-palemoon-browser-again/683018

[11] https://community.cloudflare.com/t/access-denied-to-pale-moon-desktop-browser/764330

[12] https://www.palemoon.org/

[13] https://www.falkon.org/

[14] https://www.seamonkey-project.org/

[15] https://www.palemoon.org/releasenotes.shtml

[16] https://www.theregister.com/2023/07/05/firefox_115_browser_windows/

[17] https://www.theregister.com/2025/02/10/cloudflare_q4_2024_ai_web/

[18] https://www.theregister.com/2025/01/09/uk_blog_cloudflare_subpoena/

[19] https://www.theregister.com/2024/12/13/cloudflare_2024_review/

[20] https://www.theregister.com/2024/11/27/cloudflare_logs_data_loss_incident/

[21] https://news.ycombinator.com/item?id=42953508

[22] https://developers.cloudflare.com/support/contacting-cloudflare-support/

[23] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Z8cxt9FJjItPH3TcefAC3AAAAMY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[24] https://www.theregister.com/2012/02/29/torvalds_tantrum_opensuse/

[25] https://www.acfe.com/

[26] https://whitepapers.theregister.com/



wolfetone

" According to some in the Hacker News discussion of the problem, something else that can count as suspicious – other than using niche browsers or OSes – is something as simple as asking for a URL unaccompanied by any referrer IDs. To us, that sounds like a user with good security measures that block tracking, but it seems that, to the CDN merchant, this looks like an alert to an action that isn't operated by a human. "

It's also something poor scrapers/bots do too. Often they'll just trawl through a load of links and go direct. So one tactic CloudFlare (and others) do is block or slow down requests that don't contain that tracker information. But then good scrapers/bots will always go to the root of the site, then simulate clicks through to the desired page to scrape it.

But this method that they're blocking on is for the low hanging fruit, the "swiss cheese" approach if you will.

katrinab

Take the Wall St Journal for example. My bot can scrape stock prices on it just fine, bypassing CloudFlare is waaay easier than it ought to be. Not going to publish the details of how I do it for obvious reasons.

However, just visiting the website as a regular Chrome user on Windows 11 can be quite a challenge.

Jamie Jones

Just like with the media industry and their anti-piracy efforts, it seems that the legitimate users suffer the most.

As for checking "User-Agent", surely that's the first thing a bot spoofs (the bots that ignore robots.txt on my sites do, at least), so again, it's less known legitimate browsers that set a legitimate header that are penalised.

Tubz

I have a couple of sites I use TOR to access and they too seem to have issues using Cloudfare.

Another step towards CableTV-2.0

Jusme

...You will use an approved browser (on an approved OS)

...You won't tamper with the content (block ads)

Re: Another step towards CableTV-2.0

Anonymous Coward

Adblockers like Ublock have been fighting back hard look at youtube attempts to ban them.

power without responsibility

captain veg

My own experience is that Cloudflare really don't give the slightest fleck of turd for whatever deleterious effect its "services" have on ordinary end users. If you're not actually a paying customer or law enforcement agency then you don't exist.

I've noticed them blocking access to a few sites recently on the basis of (correctly) geo-locating me in Andorra.

Absolute scumbags.

-A.

Re: power without responsibility

Lazlo Woodbine

By hosting ads on your screen, you technically are a paying user...

Re: power without responsibility

AVR

Well, you're the product at least. The payment isn't going to Cloudflare, they're not going to care.

Re: power without responsibility

Lazlo Woodbine

But you are blocking payment to Cloudflare's customer. If this happens often enough, they could be made to care...

Re: power without responsibility

myhandler

I manage a medium size site and putting it through Cloudflare was the solution for stopping the multitude of DDOS bot attacks.

It has its uses.

Even blocking Chrome on a Chromebook

SW

How's that - can't get more "corporate" that a Google browser on Google hardware - yet still blocked me this morning.

Incompetent or evil?

ptribble

As a niche browser user (Pale Moon) on a niche OS (illumos) I get hit by this.

The question really is whether this is deliberate censorship, or inability. If the latter, then the idea they can accurately identify traffic is called into question.

Not sure how superficial is the browser check

IamAProton

There are many user agent spoofers around, I use chameleon all the time and rotate the browser profile every 5 minutes to always haev a different fingerprint.

The set of profiles/user agents can be chosen in advance

https://addons.mozilla.org/en-US/firefox/addon/chameleon-ext/

Re: Not sure how superficial is the browser check

Gene Cash

This doesn't work though.

My credit union (Trumpistani for building society, I think) used Cloudflare to block my older Firefox by locking the browser up with javascript, even though I had a user agent spoofed. The browser would suddenly start using all the cores in xosview, and when I did kill -9 or kill -11 it would take 5-10 seconds for the process to actually die.

Then of course Firefox would be "helpful" by reopening the last page and locking up again.

This started happening about a week and a half ago.

This is mentioned in the sixth paragraph of the article.

Re: Not sure how superficial is the browser check

anonymous cat herder

I wonder if that is why Firefox on Android has started regularly locking up when opening a page over the last month or two. Only solution I've found is to close it and start again.

nematoad

I have just sorted out a similar problem when using Palemoon.

A kind A/c posted the following :

You can get decent user agents by running a search for "The Latest and Most Common User Agents List". Give it a try, see if it works.

I did, and it worked for my problem.

It might sort out this nasty little "feature not a bug as well."

Blackjack

Browser agents can be easily faked by botnets, this mostly just hurts users.

Gene Cash

Yes, plus a Python script doesn't have whatever javascript exploit they're using to lock up older browsers.

I wrote the script to download my credit union statement, because they broke Firefox.

Which is ironic, using a bot script to get around the bot script blocking.

Doctor Syntax

"Aside from reporting it on Cloudflare's forum, there appears to be little users can do"

There is. They can desert sites that have this affliction.

Gene Cash

Not really.

Most of the banks and credit unions here in Trumpistani use Cloudflare.

And of course they're useless when you report this as a problem. They just say "use the latest firefox" and assume you are hacking. The same thing happened when I questioned why they were setting .RU and .CN tracking cookies.

I have reported it to the NCUA and the FDIC but they don't give a shit either.

Now I have certainly stopped using a couple of vendors that use captcha. One of them was so retarded they didn't know captchas popped up. They were like "all you have to do is click 'I am human'" and I had to send them a screenshot.

Edit: I did run into the CEO of one of the vendors at Bike Week. That was an interesting conversation. We'll see if anything actually changes.

I don't believe in coincidences.

Tron

I suspect this is censorship. The big browsers can block downloading extensions, ad blockers etc. Alt browsers might not.

Early versions of Opera used to dodge this by offering the option of reporting themselves as IE. Unfortunately, browsers have been getting shorter customisation option lists.

The internet will become more restrictive with every passing week from now on courtesy of governments and big tech. The Empire is striking back. We can't do a lot about it other than hate them for ruining our net experience.

Re: I don't believe in coincidences.

Anonymous Coward

The internet will never become more restrictive with every passing week because many are fighting to stop that. There many things we can do about it.

Firefox

Philo T Farnsworth

I've been seeing "are you a robot" challenges from Cloudflare for a few weeks using Firefox, though that's probably because I've got ad blockers, anti-trackers, and NoScript plugins.

I also have been seeing intermittent blocking by Google News, alleging my IP address is engaging in "unusual" activity, which it is not.

As of this morning, after switching over to Waterfox as my default browser, Google News has been CAPTCHA challenging me every time I click on a link, even though the browser's UserAgent string is pretty vanilla:

Mozilla/5.0 (X11; Linux x86_64; rv:128.0) Gecko/20100101 Firefox/128.0

Re: Firefox

find users who cut cat tail

I am also seeing Cloudflare nonsense in normal Firefox – which I have as failsafe for sites insisting on a standard browser. Funny, a good portion of the sites work just fine in links and w3m.

Can't anything about Google as I've not visited any their site since Search started hard-requiring JavaScript.

It's crazy

Mage

Cloudfare are arrogant and stupid

Also sites using them and using also captcha etc AFTER you logged in.

Re: It's crazy

ecofeco

They always have been.

I cringe every time I have to unblock cloud flarte to view a web site. It is unnecessary and absurd and is counter to the very nature and purpose of the Internet.

Screenreader and other assistive technologies

Korev

Does this affect Screenreaders etc? If so then it's probably against the law in a number of countries under disability equality legislation.

milet

This is a known problem, caused by "Disable Autoplay" extension. Enable autoplay on sites with CloudFlare protection and voila, problem solved.

Of course, it would be even better if CloudFlare DID something about it...

thosrtanner

Where is this "Known" exactly? (And IIRC Disable Autoplay is a chrome extension, and not applicable to palemoon for instance)

If elected, Zippy pledges to each and every American a 55-year-old houseboy ...