.aspx (.vb) webpage throwing errors when published in Fasthosts

Question

.aspx (.vb) webpage throwing errors when published in Fasthosts

Ganesalingam Narenthiran 0

Hello,
My web host is Fasthosts. My server: Windows OS and ASP.Net 4.8

I created a simple dynamic web page using ASP.Net and vb. The web application is just adding two inputs.

The program works well locally.

When I try to view the web page, I get an error. I have tried to trouble shoot all weekend, with no success. I contacted Fasthosts; they said that my ASP.Net pages would not run because security reasons (my privilege is not Full, I presume). Please find below the error message and my codes. I would appreciate any advise on how to get my little test .aspx run.

http://apps.surgicalneurology.org.WebForm1.aspx

Error message:

Server Error in '/' Application.

Security Exception

__Description:__The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file. __Exception Details:__System.Security.SecurityException: Request failed. Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
`An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.`

Stack Trace:

|[SecurityException: Request failed.]
System.Security.CodeAccessSecurityEngine.ThrowSecurityException(RuntimeAssembly asm, PermissionSet granted, PermissionSet refused, RuntimeMethodHandleInternal rmh, SecurityAction action, Object demand, IPermission permThatFailed) +100
System.Security.CodeAccessSecurityEngine.ThrowSecurityException(Object assemblyOrString, PermissionSet granted, PermissionSet refused, RuntimeMethodHandleInternal rmh, SecurityAction action, Object demand, IPermission permThatFailed) +83
System.Security.CodeAccessSecurityEngine.CheckSetHelper(PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandleInternal rmh, Object assemblyOrString, SecurityAction action, Boolean throwException) +295
System.Security.CodeAccessSecurityEngine.CheckSetHelper(CompressedStack cs, PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandleInternal rmh, RuntimeAssembly asm, SecurityAction action) +73
System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMarkHandle stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName, ObjectHandleOnStack type) +0
System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName) +71
System.RuntimeType.GetType(String typeName, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark) +41
System.Type.GetType(String typeName) +31
System.CodeDom.Compiler.CompilerInfo.get_IsCodeDomProviderTypeValid() +13
System.Web.Compilation.CompilationUtil.GetRecompilationHash(CompilationSection ps) +2130
System.Web.Configuration.CompilationSection.get_RecompilationHash() +110
System.Web.Compilation.BuildManager.CheckTopLevelFilesUpToDateInternal(Int64 cachedHash) +497
System.Web.Compilation.BuildManager.CheckTopLevelFilesUpToDate(Int64 cachedHash) +53
System.Web.Compilation.BuildManager.ExecutePreAppStart() +142
System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +590| | -------- | |[SecurityException: Request failed.] System.Security.CodeAccessSecurityEngine.ThrowSecurityException(RuntimeAssembly asm, PermissionSet granted, PermissionSet refused, RuntimeMethodHandleInternal rmh, SecurityAction action, Object demand, IPermission permThatFailed) +100 System.Security.CodeAccessSecurityEngine.ThrowSecurityException(Object assemblyOrString, PermissionSet granted, PermissionSet refused, RuntimeMethodHandleInternal rmh, SecurityAction action, Object demand, IPermission permThatFailed) +83 System.Security.CodeAccessSecurityEngine.CheckSetHelper(PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandleInternal rmh, Object assemblyOrString, SecurityAction action, Boolean throwException) +295 System.Security.CodeAccessSecurityEngine.CheckSetHelper(CompressedStack cs, PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandleInternal rmh, RuntimeAssembly asm, SecurityAction action) +73 System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMarkHandle stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName, ObjectHandleOnStack type) +0 System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName) +71 System.RuntimeType.GetType(String typeName, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark) +41 System.Type.GetType(String typeName) +31 System.CodeDom.Compiler.CompilerInfo.get_IsCodeDomProviderTypeValid() +13 System.Web.Compilation.CompilationUtil.GetRecompilationHash(CompilationSection ps) +2130 System.Web.Configuration.CompilationSection.get_RecompilationHash() +110 System.Web.Compilation.BuildManager.CheckTopLevelFilesUpToDateInternal(Int64 cachedHash) +497 System.Web.Compilation.BuildManager.CheckTopLevelFilesUpToDate(Int64 cachedHash) +53 System.Web.Compilation.BuildManager.ExecutePreAppStart() +142 System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +590|

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4770.0

My .aspx:

<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="WebForm1.aspx.vb" Inherits="multiply.WebForm1" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            a:
        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
            <br />
            b:
            <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
            <br />
            <asp:Button ID="Button1" runat="server" Text="Button" />
            <br />
            <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
        </div>
    </form>
</body>
</html>

My .vb file:

Public Class WebForm1
    Inherits System.Web.UI.Page
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    End Sub
    Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim ab As Decimal
        Dim cd As Decimal
        ab = TextBox1.Text
        cd = TextBox2.Text
        Dim c As Decimal
        c = ab + cd
        Label1.Text = c
    End Sub
End Class

My web.config file:

<?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  https://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
  <system.web>
    <compilation debug="true" strict="false" explicit="true" targetFramework="4.8" />
    <httpRuntime targetFramework="4.8" />
    <customErrors mode="Off"/>
  </system.web>
  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:1659;1699;1701" />
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
    </compilers>
  </system.codedom>
</configuration>

6 answers

Your answer

Answer 1

Bruce (SqlWork.com) 79,106 Volunteer Moderator

You vb compiler setting is truncated

<compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008,40000,40008 /define:_MYTYPE="Web" /optionInfer+" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=4.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />

Answer 2

Sorry. Please find the .vb file code below

***interestingly all works well ASP.net 2. Fasthosts mentioned their current ASP.Net is 4.8

Public Class WebForm1
    Inherits System.Web.UI.Page
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    End Sub
    Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim ab As Decimal
        Dim cd As Decimal
        ab = TextBox1.Text
        cd = TextBox2.Text
        Dim c As Decimal
        c = ab + cd
        Label1.Text = c
    End Sub
End Class

Answer 3

Hi Ganesalingam Narenthiran,

I reviewed your error and code, and it seems your VB/ASPX code is fine. The issue is not with IIS or your logic, it’s about how your hosting environment runs ASP.NET.

The error:

System.Security.SecurityException: Request failed

appears during application startup, before your button click code runs. The stack trace shows:

System.CodeDom.Compiler.CompilerInfo.get_IsCodeDomProviderTypeValid() System.Web.Compilation.BuildManager.ExecutePreAppStart()

This means ASP.NET is trying to compile your page dynamically using the Roslyn compiler (added by default in modern ASP.NET 4.8 apps). Roslyn needs Full Trust to run because it launches compiler executables from bin\roslyn.

However, Fasthosts told you they run your site with restricted permissions (Medium Trust) for security. Under Medium Trust, Roslyn cannot execute, so the app fails immediately.

Why did it work on your PC? Your local machine runs under Full Trust by default, so Roslyn works fine there.

Older ASP.NET 2.0 apps didn’t use Roslyn, which is why they still work on the same host.

I managed to find three options you could try:

1. Precompile your site (recommended)

Precompiling removes the need for runtime compilation, so Roslyn never runs.

In Visual Studio:
- Publish → Settings → Precompile during publishing → Configure
- Uncheck “Allow precompiled site to be updatable”
Deploy the published output (not the raw source) to Fasthosts.

Reference: Precompiling ASP.NET Web Forms

2. Remove Roslyn and use the legacy compiler

If you can’t precompile:

Delete the <system.codedom> section from your web.config.
Remove the bin\roslyn folder from your deployment.
Redeploy the site.

This forces ASP.NET to use the older CodeDOM compiler, which usually works under Medium Trust.

3. Ask Fasthosts for Full Trust

If your hosting plan allows, request Full Trust for your app pool. Many shared hosts don’t allow this, so Options 1 or 2 are safer.

References:

Bottom line is this is a hosting trust-level issue. Precompiling or removing Roslyn usually solves it.

Once you have tried these options out, please let me know - I'd be more than happy to help!

Answer 4

Ganesalingam Narenthiran 0

@Tom Tran Thank you! I have tried (1) and (2). I just get the following error:
502 Bad Gateway

nginx/1.27.4

Answer 5

After removing the section of the web.config file relating to Rosyl and uninstalling NuGet and clearing any traces of Rosyl through Rosyn VS prompt and converting it into a web application and then rebuilding, there was no Rosyl folder. I uploaded to my web hosting (www.childneurosurgery.org/WebForm1.aspx and I get the following error (however, a simple webpages, /test.html works fine):

[SecurityException: Request for the permission of type 'System.Security.Permissions.SecurityPermission, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.]
   System.Web.Security.UrlAuthorizationModule.CheckUrlAccessForPrincipal(String virtualPath, IPrincipal user, String verb) +43
   Microsoft.AspNet.FriendlyUrls.Abstractions.UrlAuthorizationModuleWrapper.CheckUrlAccessForPrincipal(String virtualPath, IPrincipal user, String verb) +15
   Microsoft.AspNet.FriendlyUrls.FriendlyUrlRoute.GetWebObjectFactory(HttpContextBase httpContext, String modifiedVirtualPath) +159
   Microsoft.AspNet.FriendlyUrls.FriendlyUrlRoute.Resolve(HttpContextBase httpContext, IList`1 extensions, String virtualPathOverride, IFriendlyUrlRouteSupportFunctions supportFunctions) +220
   Microsoft.AspNet.FriendlyUrls.FriendlyUrlRoute.Microsoft.AspNet.FriendlyUrls.Abstractions.IFriendlyUrlRouteSupportFunctions.Resolve(HttpContextBase httpContext, IList`1 extensions, String virtualPathOverride) +16
   Microsoft.AspNet.FriendlyUrls.FriendlyUrlRoute.GetRouteData(HttpContextBase httpContext, String pathOverride, IFriendlyUrlRouteSupportFunctions supportFunctions) +140
   Microsoft.AspNet.FriendlyUrls.FriendlyUrlRoute.GetRouteData(HttpContextBase httpContext) +8
   System.Web.Routing.RouteCollection.GetRouteData(HttpContextBase httpContext) +237
   System.Web.Routing.UrlRoutingModule.PostResolveRequestCache(HttpContextBase context) +63
   System.Web.Routing.UrlRoutingModule.OnApplicationPostResolveRequestCache(Object sender, EventArgs e) +85
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +144
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +50
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +73

Share via

.aspx (.vb) webpage throwing errors when published in Fasthosts

6 answers

Your answer