I'm having this issue where fiddler will only capture traffic coming from 127.0.0.1:8888, any other traffic is CONNECT, I've tried everything to get it to capture normal.

Hello, when I examine facebook.com traffic, unfortunately fiddler cannot decrypt HTTPS traffic. Even though I click on it many times, I can't get any results. I don't have problems with other similar applications, but I have problems with Fiddler. How can I solve this?

 

Hi everyone,

I have an .net framework 4.7.2 C# WPF app running which also has a little .net 3.5 app inside it.

This is running 1500 computers in australia and has been for 18 months.

Today we started getting reports of computers having 'crashes'

Debugging has provided this info:

section: created rest options System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The request was aborted: Could not create SSL/TLS secure channel.

What we have now found out is that it is Windows 7 clients all being affected.

Importantly:

Postman and google chrome can access the api

JUST the .net seems ot be having issues.

After seeing this I have downlaoded fiddler (for first time) and we are seeing a handshake issue:

fiddler.network.https> HTTPS handshake to www.mydomain.com.au (for #710) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326


But then when i booted fiddler im also seeing the same issue:

[Fiddler] The connection to 'api.getfiddler.com' failed.  <br />System.Security.SecurityException Failed to negotiate HTTPS connection with server.fiddler.network.https&gt; HTTPS handshake to api.getfiddler.com (for #1) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. &lt; The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326                                       

 

 

So maybe the fiddler API is in fact having the same connection issue as I do, but maybe thats not really going to be noticed because its an update checker for their API but mine is my whole app??

 

Any ideas would be appreciated.

 

The last update for FiddlerCore was in 2021, is this product still being developed?

When I try to do that, it doesn't work

[NOT POSSIBLE ANYMORE, DELETE PLEASE]

1) Fiddler didn't hint for most top-level user class name anymore. For example, the following code:

• If I type code at **, it'll hint all system class without Xyz1 but it shows Xyz2.
• If I type "Xyz1." then it hint "Xyz3" so it seems to see fields/methods inside properly.

I use Fiddler in another PC (PC2) which report the exact same version (and editor's version), it hints my class properly.
*PC2 that works well has a bit lower WinNT part "WinNT 10.0.18363.0"

class Xyz1 { //Try both public, class
public static class Xyz3 {

}
}
class Handlers
{
static class Xyz2 {

}
public static function xx2(){
**
}
}

The scenario:

"Before this", I think Fiddler hint it in current PC (PC1) too. But it's abruptly missing so I try typing the new class. It hints the new class but not for the class I'll use. So I was dumbfounded and reset the script (delete the file) and retest. Because I know some pattern of code may break Fiddler format. Then "Handlers" is not in the list so I'm sure it's not about the format. I want to confirm that it normally hint top-level class name so I check it in my PC2, and it did. Then I completely uninstall-reinstall Fiddler in PC1. It fails it list any user class. I also try to swap the script to test between PC1 and PC2. PC1 always not work and PC2 always work. *I did not try to reinstall on PC2 though because it's heavily used. But it has the exact same version.

2) Script editor from "Customize Rules..." menu change after close and open it for the 2nd time - even without restart Fiddler Classic. Folding feature is missing and comment will be green instead of gray as after fresh install Fiddler Classic. I usually use this variant though, maybe because the gray comment version is found only once after fresh install. Embedded editor in tab is green with folding though. But problem 1) hint never work anywhere.

Greetings,

I am trying to figure out an issue that I was given. There are two apps A and B. 

A is used to authenticate users and passes a token to B and B adds a cookie. Something strange happens when the cookie expires or after a hard browser reset. 

 

WITHOUT FIDDLER: 

User hits app A enters credentials and gets forwarded to app B. However, for about 5 seconds the browsers black "xxx took too long to respond" error screen shows but then magically the default page is rendered soon afterward. This only seems to occur when the cookie has expired or after an extended amount of time.

 

WITH FIDDLER: (SEE SESSIONS 61, 71 and 83)

When I perform the same scenario in fiddler, where I would expect the black "xxx took too long to respond" screen, I get the certificate error screen attached with the open lock icon. I have to dismiss that three time. While I am dismissing the ssl tunnel errors the default user page is rendering.

The correlation is about the same time I get the lock dialog(s) in fiddle is the same place I get the black browser error screen and the app seems to be loading in the background and the refreshes once fully loaded.

My thought is there is a https-->http request being "partially" blocked from A-->B as B is http only with no certs. The devs tell me they can't find a request being made that is https. So, I can't figure out where the ssl tunnel is coming from (see screen capture). My thoughts are.

1. The devs missed something and one of the calls is http.

2. Some network appliance is attempting to convert the call to https, though there are no url rewrites on the IIS server. 

 

Any input would be helpful. Can anyone see what would cause a black "xxx took too long to respond"  to render while the default page is loading. It feels like one of those weird scenarios where the request was changed before it was fully read or something else arcane like that.

 

Gentlemen,
Ladies,

My question is relatively simple. I do all of my work on a Mac Studio M1, using OsX.

When doing .NET development I usually run Visual Studio on Windows 11 on ARM or in another Virtual machine, run from an actual Windows machine.

I'm not a big fan of the 2nd option, since the machine can be sluggish at times, but... the VM has Fiddler Everywhere up & running, the Parallels version does not.

Windows for ARM allows me to install the application, but it does not start up.

I do have Fiddler installed on my Mac itself, so I was wondering... is there a way I can monitor/capture what's occurring on my Parallels machine?

Trying to debug a chunked encoding response that looks correct to me. But when clicking on decode in response inspector I get the error "HTTP Error.. The chunked content is corrupt. Chunk Length was malformed. Offset 19". 
My question is, why does Fiddler think this is corrupt as the chunk lengths and encoding seems correct. And more specifically, how do I know what position "offset 19" is referring to so I can investigate further?