Captcha question when using Fiddler

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Fiddler Classic
Alex
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Alex asked on 30 Nov 2022, 08:29 PM

The following page loads ok when not using Fiddler Classic as a proxy...

https://www.investing.com/currencies/eur-usd

But if I use Fiddler, the chart on the page will not load! I checked everything and the problem seems to be related to the fact that some resources needed by the page above do not load, and that is because Cloudflare is returning a captcha question instead of data. One such resource file is this, for which I am always getting a captcha when using Fiddler (it works ok otherwise):

https://api.investing.com/api/financialdata/table/list/1?fieldmap=general.slim

Is there any way to fix this, please? I would like to pass all the traffic through Fiddler, and have the page load ok every time.

My Fiddler is not set to make any kind of changes to the page headers, or its content. So I guess Cloudflare is using other ways to detect when traffic is not coming directly from a web browser.

Thank you!

Alex

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Nick Iliev
Telerik team
answered on 05 Dec 2022, 08:35 AM

Hello Alex,

 

Many Captcha tools use a cognitive approach to when/why they should appear. They usually occur when they assume requests from a specific IP address are coming more often than usual (or similar logic). So that said, there is not much you could do from Fiddler's side - when the Captcha appears, it requires human interaction, and this is its sole purpose (to prevent interaction from automated tools).

As a side note, there are some third-party automated Captcha solvers, but I can't recommend any specific tool.

 

Regards,
Nick Iliev
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Alex
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commented on 05 Dec 2022, 10:38 AM

Thank you for the clarification!
thanh
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commented on 22 Nov 2023, 06:20 AM

Your response doesn't convince me because Cloudflare detected differences in Cipher Suites and TLS Extensions, unlike a typical browser. This is a shortfall compared to other common publishers. You can visit https://browserleaks.com/tls to see the difference.
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