We are seeing the following on an install of BlogEngine.NET 3.3.6.0 on Windows 2012 with Recaptcha - I think that version 1 has been made end-of-life and the blog is still trying to use it...



Log Name: Application
Source: ASP.NET 4.0.30319.0
Date: 12/06/2018 10:20:47
Event ID: 1309
Task Category: Web Event
Level: Warning
Keywords: Classic
User: N/A
Computer: %COMPUTERNAME%.domain.suffix
Description:
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 6/12/2018 10:20:47 AM
Event time (UTC): 6/12/2018 9:20:47 AM
Event ID: 5f2f4368840544c7ac6c8dfd3ffd8318
Event sequence: 1618
Event occurrence: 1
Event detail code: 0

Application information:
Application domain: /LM/W3SVC/34/ROOT-1-131732091164941361
Trust level: Full
Application Virtual Path: /
Application Path: E:\Websites\www\host.domain.suffix\
Machine name: %COMPUTERNAME%

Process information:
Process ID: 24664
Process name: w3wp.exe
Account name: IIS APPPOOL\sircles.info

Exception information:
Exception type: ArgumentNullException
Exception message: Value cannot be null.
Parameter name: Challenge
at Recaptcha.RecaptchaValidator.Validate() in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\Custom\Extensions\Recaptcha\RecaptchaValidator.cs:line 110
at App_Code.Controls.RecaptchaControl.Validate() in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\Custom\Extensions\Recaptcha\RecaptchaControl.cs:line 468
at contact.btnSend_Click(Object sender, EventArgs e) in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\contact.aspx.cs:line 78
at System.Web.UI.WebControls.Button.OnClick(EventArgs e)
at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)



Request information:
https://host.domain.suffix:443/contact.aspx 
Request path: /contact.aspx
User host address: 185.206.82.38
User:
Is authenticated: False
Authentication Type: hostEngine.NET Custom Identity
Thread account name: IIS APPPOOL\sircles.info

Thread information:
Thread ID: 96
Thread account name: IIS APPPOOL\sircles.info
Is impersonating: False
Stack trace: at Recaptcha.RecaptchaValidator.Validate() in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\Custom\Extensions\Recaptcha\RecaptchaValidator.cs:line 110
at App_Code.Controls.RecaptchaControl.Validate() in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\Custom\Extensions\Recaptcha\RecaptchaControl.cs:line 468
at contact.btnSend_Click(Object sender, EventArgs e) in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\contact.aspx.cs:line 78
at System.Web.UI.WebControls.Button.OnClick(EventArgs e)
at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)


Custom event details:

Event Xml:



1309
3
3
0x80000000000000

2223371
Application
%COMPUTERNAME%.domain.suffix



3005
An unhandled exception has occurred.
6/12/2018 10:20:47 AM
6/12/2018 9:20:47 AM
5f2f4368840544c7ac6c8dfd3ffd8318
1618
1
0
/LM/W3SVC/34/ROOT-1-131732091164941361
Full
/
E:\Websites\www\host.domain.suffix\
%COMPUTERNAME%


24664
w3wp.exe
IIS APPPOOL\sircles.info
ArgumentNullException
Value cannot be null.
Parameter name: Challenge
at Recaptcha.RecaptchaValidator.Validate() in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\Custom\Extensions\Recaptcha\RecaptchaValidator.cs:line 110
at App_Code.Controls.RecaptchaControl.Validate() in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\Custom\Extensions\Recaptcha\RecaptchaControl.cs:line 468
at contact.btnSend_Click(Object sender, EventArgs e) in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\contact.aspx.cs:line 78
at System.Web.UI.WebControls.Button.OnClick(EventArgs e)
at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)


https://host.domain.suffix:443/contact.aspx
/contact.aspx
185.206.82.38


False
hostEngine.NET Custom Identity
IIS APPPOOL\sircles.info
96
IIS APPPOOL\sircles.info
False
at Recaptcha.RecaptchaValidator.Validate() in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\Custom\Extensions\Recaptcha\RecaptchaValidator.cs:line 110
at App_Code.Controls.RecaptchaControl.Validate() in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\Custom\Extensions\Recaptcha\RecaptchaControl.cs:line 468
at contact.btnSend_Click(Object sender, EventArgs e) in C:\rtur\src\Github\be\latest\hostEngine.NET\hostEngine\hostEngine.NET\contact.aspx.cs:line 78
at System.Web.UI.WebControls.Button.OnClick(EventArgs e)
at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

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