Hello,

I've been using FiddlerCore on Windows for some time now and it's been great. However some of my users have recently started to report

issues where the proxy fails to connect to anything. I've checked the logs and every time this user happens is because of BCCertMaker.

This is what's shown in the log:

Fiddler.BCCertMaker> Failed to create certificate for localhost: Key not valid for use in specified state. at System.Security.Cryptography.Utils.CreateProvHandle(CspParameters parameters, Boolean randomKeyContainer) at System.Security.Cryptography.Utils.GetKeyPairHelper(CspAlgorithmType keyType, CspParameters parameters, Boolean randomKeyContainer, Int32 dwKeySize, SafeProvHandle& safeProvHandle, SafeKeyHandle& safeKeyHandle) at System.Security.Cryptography.RSACryptoServiceProvider.GetKeyPair() at System.Security.Cryptography.RSACryptoServiceProvider..ctor(Int32 dwKeySize, CspParameters parameters, Boolean useDefaultKeySize) at BCCertMaker.BCCertMaker.ConvertBCPrivateKeyToDotNet(RsaPrivateCrtKeyParameters bcPVK, String sKeyName) at BCCertMaker.BCCertMaker.CreateCertificateFromCA(String sCN, X509Certificate caCert, AsymmetricKeyParameter caKey) at BCCertMaker.BCCertMaker.MakeNewCert(String sHostname)

I've done research on this error and it's not clear what it's cause is but I've found that it can be solved by deleting

the "Crypto" folder in %AppData%\Microsoft\. This is clearly not ideal and would appreciate if someone had an idea on how to work

around this issue in the future.

Thanks.

Hi,

I couldn't find where I can customize rules on Fiddler 0.3.0, is this available?

Thanks,

Jzy

I have been trying to get Fiddler configured to decrypt HTTPS traffic on a Citrix image.  We need this for diagnostics\troubleshooting an issue we are having.  When I run through the process to Trust the Root Certificate I get the normal SCARY message and when I choose "Yes" I get an error about being unable to configure Windows to Trust the Fiddler Root Certificate.  Here are the details in the log:

-= Fiddler Event Log =-
See http://fiddler2.com/r/?FiddlerLog for details.

07:56:11:3776 Fiddler Running...
07:56:11:3932 Windows 8+ AppContainer isolation feature detected.
07:56:17:9514 Assembly 'C:\Program Files (x86)\Fiddler2\CertMaker.dll' was not found. Using default Certificate Generator.
07:56:17:9514 /Fiddler.CertMaker> Using .‰+˜ for certificate generation; UseWildcards=True.
07:56:21:2343 DefaultCertMaker: GetRootCertificate() did not find the root in the Windows TrustStore.
07:56:21:2343 /Fiddler.CertMaker> Caller was in ApartmentState: STA; hopping to Threadpool
07:56:21:2343 /Fiddler.CertMaker> Invoking CertEnroll for Subject: CN=DO_NOT_TRUST_FiddlerRoot, O=DO_NOT_TRUST, OU=Created by http://www.fiddler2.com; Thread's ApartmentState: MTA
07:56:21:2850 !ERROR: Failed to generate Certificate using CertEnroll. System.Reflection.TargetInvocationException Exception has been thrown by the target of an invocation. < CertEnroll::CX509PrivateKey::Create: The profile for the user is a temporary profile. 0x80090024 (-2146893788 NTE_TEMPORARY_PROFILE)
07:56:24:4304 DefaultCertMaker: GetRootCertificate() did not find the root in the Windows TrustStore.
07:56:24:4304 !Fiddler.CertMaker> The Root certificate could not be found.
07:58:00:3753 Setting upstream gateway to none
07:58:16:7514 DefaultCertMaker: GetRootCertificate() did not find the root in the Windows TrustStore.
07:58:16:7514 !Fiddler.CertMaker> The Root certificate could not be found.
07:58:29:0623 DefaultCertMaker: GetRootCertificate() did not find the root in the Windows TrustStore.
07:58:29:0623 !Fiddler.CertMaker> The Root certificate could not be found.
08:03:20:0051 DefaultCertMaker: GetRootCertificate() did not find the root in the Windows TrustStore.
08:03:20:0051 /Fiddler.CertMaker> Caller was in ApartmentState: STA; hopping to Threadpool
08:03:20:0051 /Fiddler.CertMaker> Invoking CertEnroll for Subject: CN=DO_NOT_TRUST_FiddlerRoot, O=DO_NOT_TRUST, OU=Created by http://www.fiddler2.com; Thread's ApartmentState: MTA
08:03:20:0051 !ERROR: Failed to generate Certificate using CertEnroll. System.Reflection.TargetInvocationException Exception has been thrown by the target of an invocation. < CertEnroll::CX509PrivateKey::Create: The profile for the user is a temporary profile. 0x80090024 (-2146893788 NTE_TEMPORARY_PROFILE)
08:03:39:1731 DefaultCertMaker: GetRootCertificate() did not find the root in the Windows TrustStore.
08:03:39:1731 !Fiddler.CertMaker> The Root certificate could not be found.
08:03:46:3336 DefaultCertMaker: GetRootCertificate() did not find the root in the Windows TrustStore.
08:03:46:3336 /Fiddler.CertMaker> Caller was in ApartmentState: STA; hopping to Threadpool
08:03:46:3336 /Fiddler.CertMaker> Invoking CertEnroll for Subject: CN=DO_NOT_TRUST_FiddlerRoot, O=DO_NOT_TRUST, OU=Created by http://www.fiddler2.com; Thread's ApartmentState: MTA
08:03:46:3336 !ERROR: Failed to generate Certificate using CertEnroll. System.Reflection.TargetInvocationException Exception has been thrown by the target of an invocation. < CertEnroll::CX509PrivateKey::Create: The profile for the user is a temporary profile. 0x80090024 (-2146893788 NTE_TEMPORARY_PROFILE)
10:06:29:9758 DefaultCertMaker: GetRootCertificate() did not find the root in the Windows TrustStore.
10:06:29:9758 !Fiddler.CertMaker> The Root certificate could not be found.

Hi everyone,

I finally figured out how to capture traffic with Telerik Fiddler on my Android device. I can capture websites such as telerik.com but I can't get the POST/GET requests of a app. How can I fix this?

Thanks.

When trying to start Fiddler on MacOS 10.14 (Mojave), I see the following crash.  Has anyone gotten Fiddler working on Mojave?

$ mono Fiddler.exe

WARNING: The Carbon driver has not been ported to 64bits, and very few parts ofWindows.Forms will work properly, or at all
Stacktrace:

  at <unknown> <0xffffffff>
  at (wrapper managed-to-native) System.Windows.Forms.XplatUICarbon.CGDisplayBounds (intptr) [0x00002] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.XplatUICarbon.get_WorkingArea () [0x00005] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.XplatUICarbon.get_VirtualScreen () [0x00000] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.XplatUI.get_VirtualScreen () [0x00000] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.Screen..cctor () [0x00034] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at (wrapper runtime-invoke) object.runtime_invoke_void (object,intptr,intptr,intptr) [0x0001e] in <14f1e720d53a4a6a8800252bec102319>:0
  at <unknown> <0xffffffff>
  at System.Windows.Forms.Form.get_CreateParams () [0x00157] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.Control.CreateHandle () [0x0002a] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.Form.CreateHandle () [0x00000] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.Control.CreateControl () [0x00039] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.Control.SetVisibleCore (bool) [0x00057] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.Form.SetVisibleCore (bool) [0x00065] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.Control.set_Visible (bool) [0x00009] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.Control.Show () [0x00000] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at (wrapper remoting-invoke-with-check) System.Windows.Forms.Control.Show () [0x00031] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at Fiddler.frmViewer.‹• (string[]) [0x00081] in <09623c708fdb40a483cea147bbea7a7f>:0
  at Fiddler.frmViewer.‡• (string[]) [0x00016] in <09623c708fdb40a483cea147bbea7a7f>:0
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void_object (object,intptr,intptr,intptr) [0x0004e] in <09623c708fdb40a483cea147bbea7a7f>:0
exception inside UnhandledException handler: The type initializer for 'System.Windows.Forms.Screen' threw an exception.

[ERROR] FATAL UNHANDLED EXCEPTION: System.TypeInitializationException: The typeinitializer for 'System.Windows.Forms.Screen' threw an exception. ---> System.NullReferenceException: Object reference not set to an instance of an object
  at (wrapper managed-to-native) System.Windows.Forms.XplatUICarbon.CGDisplayBounds(intptr)
  at System.Windows.Forms.XplatUICarbon.get_WorkingArea () [0x00005] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.XplatUICarbon.get_VirtualScreen () [0x00000] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.XplatUI.get_VirtualScreen () [0x00000] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.Screen..cctor () [0x00034] in <7cb6368c5ba549ff8a02965fd9de701e>:0
   --- End of inner exception stack trace ---
  at System.Windows.Forms.MessageBox+MessageBoxForm.InitFormsSize () [0x00002] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at System.Windows.Forms.MessageBox+MessageBoxForm.RunDialog () [0x0000f] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at (wrapper remoting-invoke-with-check) System.Windows.Forms.MessageBox+MessageBoxForm.RunDialog()
  at System.Windows.Forms.MessageBox.Show (System.Windows.Forms.IWin32Window owner, System.String text, System.String caption, System.Windows.Forms.MessageBoxButtons buttons, System.Windows.Forms.MessageBoxIcon icon) [0x0000b] in <7cb6368c5ba549ff8a02965fd9de701e>:0
  at Fiddler.FiddlerApplication.DoNotifyUser (System.Windows.Forms.IWin32WindowownerWnd, System.String sMessage, System.String sTitle, System.Windows.Forms.MessageBoxIcon oIcon) [0x0002c] in <09623c708fdb40a483cea147bbea7a7f>:0
  at Fiddler.FiddlerApplication.DoNotifyUser (System.String sMessage, System.String sTitle, System.Windows.Forms.MessageBoxIcon oIcon) [0x00000] in <09623c708fdb40a483cea147bbea7a7f>:0
  at Fiddler.FiddlerApplication.ReportException (System.Exception eX, System.String sTitle, System.String sCallerMessage) [0x001a4] in <09623c708fdb40a483cea147bbea7a7f>:0
  at Fiddler.FiddlerApplication.ReportException (System.Exception ‚) [0x00006] in <09623c708fdb40a483cea147bbea7a7f>:0
  at Fiddler.frmViewer.• (System.Object, System.UnhandledExceptionEventArgs •) [0x00006] in <09623c708fdb40a483cea147bbea7a7f>:0

I am using Fiddler with HTTPS decoding for development purposes (some AutoResponder rules), but recently Fiddler has started to just randomly block all HTTPS traffic at some point. That is, I am running Fiddler and everything works, and then suddenly it stops, and I get timeout on all HTTPS requests.

What I know so far:

1. Only HTTPS traffic stops, other traffic is not affected
2. Cancelling HTTPS decryption or network capture returns everything to normal (expected)
3. Restarting Fiddler helps for about a minute and then traffic stops again
4. Port 443 is not blocked, telnetting hosts on port 443 works just fine

How can I troubleshoot this issue?

Thanks in advance.

Launching and closing Fiddler on Mac prompts for admin authN as it tries to configure the network(WiFi adapter in my case.)

I assume it's doing this to set the proxy. Does anyone know how to give Fiddler rights to make these changes whenever necessary, without the authN prompt?

Thanks

What I am wanting to achieve I think can be done with Fiddler Core, but I am not really a developer, I know enough to modify code and compile it but not to start from scratch.

This is what I want to achieve, I want to listen for a specific URL and POST value, then change the response (which I can do in Fiddler no problem), I want to then compile these settings into a standalone exe with no user interface or options, so i can simply doubel click and have it work on any pc. Since this would seem like a fairly standard use of Fiddlercore, is there a sample project I can download to start me off?

Slightly off topic to the above, rather than wait for the response from the server, can I just respond automatically (maybe add some latency first) and drop the real response if/when it comes?

thanks!

Hi,

I'm trying to use Fiddler Everywhere on macOS Mojave (10.14.4) and the proxy does not appear to enable after clicking the Capture button.  When I initially installed Fiddler and opened it, I was prompted for my password (but it still did not appear to be capturing any networking traffic).  I also got the password prompt the first time I closed the app.

I have since re-opened the app a few times and tried to click the Capture button, but nothing happens.  I also no longer ever get any password prompts (either on app open/close/capture button click).  I've tried to uninstall + reinstall the app as well with no change in behavior.

I also tried to run the app using sudo (using the following command):
sudo /Applications/Progress\ Telerik\ Fiddler.app/Contents/MacOS/Progress\ Telerik\ Fiddler

Please find the logs (electon.log and netcore.log) attached.

Any idea what might be going wrong?

Thanks

I'd like to be able to decode/inspect websocket messages (messages are 20-byte binary) so that each message can appear in a human readable way.  We basically just want to extend/add a custom websocket inspector which will show the selected message after it's been custom "decoded".  I have purchased Debugging with Fiddler Second Edition, but don't see any guidance for implementing a custom Websockets inspector.

Any guidance would be greatly appreciated!

Thanks!

Jim