Dear all,

I downloaded now fre (without paying) Fiddler to do some post tests, but as now I don't know how to enter username and password to authenticate to web service address, that was given to me. As I'm new completely to Fiddler, can anyone help me, please? I read that I need to enter Tools and something else, but I don't find it. Is tools menu under payments?

 

Thanks

 

Francesco

Some servers react differently depending on the Client Hello. Is there some way to mimic the hello of applications like Chrome?
Chrome for example uses its own ssl library which for example provides GREASE. Which library does Fiddler use on a Linux system ?

I found: https://www.telerik.com/blogs/fiddler-and-modern-tls-versions

Which seems to go a bit in the direction of customizing the client-server connection. Is it possible to use selected ciphers and extensions?

For reference:
https://github.com/refraction-networking/utls
https://engineering.salesforce.com/tls-fingerprinting-with-ja3-and-ja3s-247362855967

My english is bad, sorry

I tried to crack traffic on Fiddler but it doesn't show up, why did I have such a problem

I get the following exception on both of my computers - one with OS Win10 2004, one with Win10 1909.

With version 4.6.20171.14978 everything works fine. But when installing the current version (even a clean install) fiddler fails at startup with a message that states that a foldername is invalid.

I tried to run it as administrator, as normal user, after several resatarts and on two computers - it's always the same. Other topics in the forum didn't help.

Here is the exception:

 

---------------------------
Awww, Fiddlesticks!
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Fiddler has encountered an unexpected problem. If you believe this is a bug in Fiddler, please copy this message by hitting CTRL+C, and submit a bug report at http://www.telerik.com/forums/fiddler.

Bei der Komposition ist ein Kompositionsfehler aufgetreten. Die Ursache wird unten angegeben. Die CompositionException.Errors-Eigenschaft liefert genauere Informationen.

1) Der Verzeichnisname ist ungültig

Ergebnis: Ausnahme beim Erstellen einer Instanz vom Typ "Telerik.NetworkConnections.NetworkConnectionsManager".

Ergebnis: Teil "Telerik.NetworkConnections.NetworkConnectionsManager" kann nicht aktiviert werden.

Element: Telerik.NetworkConnections.NetworkConnectionsManager -->  Telerik.NetworkConnections.NetworkConnectionsManager -->  AssemblyCatalog (Assembly="Telerik.NetworkConnections, Version=0.1.2.0, Culture=neutral, PublicKeyToken=67cb91587178ac5a")

Ergebnis: Export "Telerik.NetworkConnections.NetworkConnectionsManager (ContractName="Telerik.NetworkConnections.NetworkConnectionsManager")" kann nicht aus dem Teil "Telerik.NetworkConnections.NetworkConnectionsManager" abgerufen werden.

Element: Telerik.NetworkConnections.NetworkConnectionsManager (ContractName="Telerik.NetworkConnections.NetworkConnectionsManager") -->  Telerik.NetworkConnections.NetworkConnectionsManager -->  AssemblyCatalog (Assembly="Telerik.NetworkConnections, Version=0.1.2.0, Culture=neutral, PublicKeyToken=67cb91587178ac5a")

Type: System.ComponentModel.Composition.CompositionException
Source: System.ComponentModel.Composition
   bei System.ComponentModel.Composition.Hosting.CompositionServices.GetExportedValueFromComposedPart(ImportEngine engine, ComposablePart part, ExportDefinition definition)

   bei System.ComponentModel.Composition.Hosting.CatalogExportProvider.GetExportedValue(CatalogPart part, ExportDefinition export, Boolean isSharedPart)

   bei System.ComponentModel.Composition.Primitives.Export.get_Value()

   bei System.ComponentModel.Composition.ExportServices.GetCastedExportedValue[T](Export export)

   bei Fiddler.Proxy.() in C:\Jenkins\Fiddler_Windows\workspace\FiddlerCore\FiddlerCore.Shared\Common\Core\Proxy.cs:Zeile 283.

   bei Fiddler.Proxy..ctor(Boolean isPrimary, ProxySettings upstreamProxySettings) in C:\Jenkins\Fiddler_Windows\workspace\FiddlerCore\FiddlerCore.Shared\Common\Core\Proxy.cs:Zeile 210.

   bei Fiddler.frmViewer.‹•(String[] ˆ•) in C:\Jenkins\Fiddler_Windows\workspace\Fiddler2\Fiddler.Shared\Viewer.cs:Zeile 3339.

   bei Fiddler.frmViewer.‡•(String[] ˆ•) in C:\Jenkins\Fiddler_Windows\workspace\Fiddler2\Fiddler.Shared\Viewer.cs:Zeile 3164.

Fiddler v5.0.20202.18177 (x64 AMD64) [.NET 4.0.30319.42000 on Microsoft Windows NT 10.0.19041.0] 
---------------------------
OK   
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Fiddler 5.0.20202 crashes on start on ReactOS 

Additional information is here https://jira.reactos.org/browse/CORE-17175

 

Could please you give a hint, the problem in which Windows library can cause such an error as shown on the screenshot?

 

ReactOS is a free and open-source operating system for amd64/i686 personal computers intended to be binary-compatible with computer programs and device drivers made for Windows  XP\ Server 2003

 

 

i am using fiddler to sniff HTTP traffics on mobile
but the app is forbidden for my IP and region and i need use v p n to
can use app
so my question is how can i use v p n on my phone for that?Because if i
open a v p n,the connection with fiddler will disconnect and fiddler
cant debug the traffics

Hello,

I am trying to monitor the WCF calls from a .NET application to a .NET service. Both are company internal but not owned by my team, so I can't change them. Both are running on my machine. The calls are sent via HTTPS. The requests are mostly using the machine name but some are also done to localhost. Is there any way to achieve what I need? I tried already about 100 different configurations, reinsured that the certificates are installed everywhere and so on. 

As Gateway I have set System Proxy but there is no such proxy.

In the session list I have connect entries and nothing else from the application I am interested in. But I am able to monitor the calls when opening the corresponding web pages e.g. and I also see multiple other requests from various applications.

In the Fiddler Log I have plenty of messages like these:

13:23:14:3506 [Fiddler] No HTTPS request was received from (xxxx) new client socket, port xxx.
13:23:19:3946 !SecureClientPipeDirect failed: System.IO.IOException Authentication failed because the remote party has closed the transport stream. for pipe (CN=xxxx, O=DO_NOT_TRUST_BC, OU=Created by http://www.fiddler2.com)

I also tried setting

<defaultProxy>
      <proxy bypassonlocal="false" usesystemdefault="true" />
</defaultProxy>

in the client application config but that didn't help either.

I checked really a lot of threads here and on SO and I couldn't figure it out. I would be grateful for any advice.

Android 7.0 

Using Fiddler as a proxy to decrypt https traffic from a browser on the phone works ok. However, when using some apps I get:
Trust anchor for certification path not found

Is there a way around this?

 

before i use fiddler, there is no certificate in my pc,

when i use fiddler to decrypt https traffic,operate like picture 1.png,,there are three certificates in my pc,picture 2-1,2-2,2-3

 

how to remove certificates from pc?

i operate like picture 3-1.png，，，but still have one certificate in my pc,picture 3-2.png  why?

Im trying to decrypt the traffic from an application that used to work in the past months without any issue, however today when i tried to view the traffic i just saw this error in fiddler:

 

fiddler.network.https> HTTPS handshake to 104.28.25.251 (for #73) 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

 

Im not sure what im supposed to do here, seems like there is an issue with the Protocols that its using?