Adding FTP Deny URL Sequences <add>

The <add> element of the <denyUrlSequences> collection specifies a unique sequence of characters to add to the collection of denied URL sequences for FTP 7.

This substatus allows Web administrators to analyze their IIS logs and identify potential threats.

With Windows 7 and Windows Server 2008 R2, the FTP 7.5 service ships as a feature for IIS 7.5, so downloading the FTP service is no longer necessary.

To support FTP publishing for your Web server, you must install the FTP service. To do so, use the following steps.

1. On the taskbar, click Server Manager.

2. In Server Manager, click the Manage menu, and then click Add Roles and Features.

3. In the Add Roles and Features wizard, click Next. Select the installation type and click Next. Select the destination server and click Next.

4. On the Server Roles page, expand Web Server (IIS), and then select FTP Server.

   Note

   To support ASP.Membership authentication or IIS Manager authentication for the FTP service, you will need to select FTP Extensibility, in addition to FTP Service.
   .

5. Click Next, and then on the Select features page, click Next again.

6. On the Confirm installation selections page, click Install.

7. On the Results page, click Close.

1. On the Start screen, move the pointer all the way to the lower left corner, right-click the Start button, and then click Control Panel.

2. In Control Panel, click Programs and Features, and then click Turn Windows features on or off.

3. Expand Internet Information Services, and then select FTP Server.

   Note

   To support ASP.Membership authentication or IIS Manager authentication for the FTP service, you will also need to select FTP Extensibility.
   

4. Click OK.

5. Click Close.

1. On the taskbar, click Start, point to Administrative Tools, and then click Server Manager.

2. In the Server Manager hierarchy pane, expand Roles, and then click Web Server (IIS).

3. In the Web Server (IIS) pane, scroll to the Role Services section, and then click Add Role Services.

4. On the Select Role Services page of the Add Role Services Wizard, expand FTP Server.

5. Select FTP Service.

   Note

   To support ASP.Membership authentication or IIS Manager authentication for the FTP service, you will also need to select FTP Extensibility.
   

6. Click Next.

7. On the Confirm Installation Selections page, click Install.

8. On the Results page, click Close.

1. On the taskbar, click Start, and then click Control Panel.

2. In Control Panel, click Programs and Features, and then click Turn Windows Features on or off.

3. Expand Internet Information Services, and then FTP Server.

4. Select FTP Service.

   Note

   To support ASP.Membership authentication or IIS Manager authentication for the FTP service, you will also need to select FTP Extensibility.
   

5. Click OK.

1. Download the installation package from the following URL:

   • https://www.iis.net/expand/FTP

2. Follow the instructions in the following walkthrough to install the FTP service:

   • Installing and Troubleshooting FTP 7

1. Open Internet Information Services (IIS) Manager:

   • If you are using Windows Server 2012 or Windows Server 2012 R2:

     • On the taskbar, click Server Manager, click Tools, and then click Internet Information Services (IIS) Manager.

   • If you are using Windows 8 or Windows 8.1:

     • Hold down the Windows key, press the letter X, and then click Control Panel.
     • Click Administrative Tools, and then double-click Internet Information Services (IIS) Manager.

   • If you are using Windows Server 2008 or Windows Server 2008 R2:

     • On the taskbar, click Start, point to Administrative Tools, and then click Internet Information Services (IIS) Manager.

   • If you are using Windows Vista or Windows 7:

     • On the taskbar, click Start, and then click Control Panel.
     • Double-click Administrative Tools, and then double-click Internet Information Services (IIS) Manager.

2. In the Connections pane, go to the site or directory for which you want to modify your request filtering settings.

3. In the Home pane, double-click FTP Request Filtering.
   

4. In the FTP Request Filtering pane, click the Denied URL Sequences tab.
   

5. Click Add URL Sequence... in the Actions pane.

6. In the Add Deny Sequence dialog box, enter the URL sequence that you wish to block.
   

7. Click OK.

The <add> element of the <denyUrlSequences> collection is configured at the global, site or URL level.

None.

The following sample illustrates several security-related configuration settings in the <system.ftpServer> element for an FTP site. More specifically, the <location> settings in this example demonstrate how to:

• Specify an FTP authorization rule for read and write access for the administrators group.
• Specify FTP request filtering options that deny *.exe, *.bat, and *.cmd files.
• Specify FTP request limits for a maximum content length of 1000000 bytes and a maximum URL length of 1024 bytes.
• Block FTP access to the _vti_bin virtual directory, which is used with the FrontPage Server Extensions.
• Specify FTP IP filtering options that allow access from 127.0.0.1 and deny access from the 169.254.0.0/255.255.0.0 range of IP addresses.

<location path="ftp.example.com">
  <system.ftpServer>
    <security>
      <authorization>
        <add accessType="Allow" roles="administrators" permissions="Read, Write" />
      </authorization>
      <requestFiltering>
        <fileExtensions allowUnlisted="true">
          <add fileExtension=".exe" allowed="false" />
          <add fileExtension=".bat" allowed="false" />
          <add fileExtension=".cmd" allowed="false" />
        </fileExtensions>
        <requestLimits maxAllowedContentLength="1000000" maxUrl="1024" />
        <hiddenSegments>
          <add segment="_vti_bin" />
        </hiddenSegments>
      </requestFiltering>
      <ipSecurity enableReverseDns="false" allowUnlisted="true">
        <add ipAddress="127.0.0.1" allowed="true" />
        <add ipAddress="169.254.0.0" subnetMask="255.255.0.0" allowed="false" />
      </ipSecurity>
    </security>
  </system.ftpServer>
</location>

The following examples will deny the URL sequence "bin" for FTP, which will prevent access to the "bin", "_vti_bin", or "cgi-bin" paths, and also prevent uploading files with a file name extension of ".bin."

appcmd.exe set config "Default Web Site" -section:system.ftpServer/security/requestFiltering /+"denyUrlSequences.[sequence='bin']" /commit:apphost

using System;
using System.Text;
using Microsoft.Web.Administration;


internal static class Sample
{
   private static void Main()
   {
      using (ServerManager serverManager = new ServerManager())
      {
         Configuration config = serverManager.GetApplicationHostConfiguration();
         ConfigurationSection requestFilteringSection = config.GetSection("system.ftpServer/security/requestFiltering", "Default Web Site");
         ConfigurationElementCollection denyUrlSequencesCollection = requestFilteringSection.GetCollection("denyUrlSequences");

         ConfigurationElement addElement = denyUrlSequencesCollection.CreateElement("add");
         addElement["sequence"] = @"bin";
         denyUrlSequencesCollection.Add(addElement);

         serverManager.CommitChanges();
      }
   }
}

Imports System
Imports System.Text
Imports Microsoft.Web.Administration

Module Sample
   Sub Main()
      Dim serverManager As ServerManager = New ServerManager
      Dim config As Configuration = serverManager.GetApplicationHostConfiguration
      Dim requestFilteringSection As ConfigurationSection = config.GetSection("system.ftpServer/security/requestFiltering", "Default Web Site")
      Dim denyUrlSequencesCollection As ConfigurationElementCollection = requestFilteringSection.GetCollection("denyUrlSequences")

      Dim addElement As ConfigurationElement = denyUrlSequencesCollection.CreateElement("add")
      addElement("sequence") = "bin"
      denyUrlSequencesCollection.Add(addElement)

      serverManager.CommitChanges()
   End Sub
End Module

var adminManager = new ActiveXObject('Microsoft.ApplicationHost.WritableAdminManager');
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST";
var requestFilteringSection = adminManager.GetAdminSection("system.ftpServer/security/requestFiltering", "MACHINE/WEBROOT/APPHOST/Default Web Site");
var denyUrlSequencesCollection = requestFilteringSection.ChildElements.Item("denyUrlSequences").Collection;

var addElement = denyUrlSequencesCollection.CreateNewElement("add");
addElement.Properties.Item("sequence").Value = "bin";
denyUrlSequencesCollection.AddElement(addElement);

adminManager.CommitChanges();

Set adminManager = createObject("Microsoft.ApplicationHost.WritableAdminManager")
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST"
Set requestFilteringSection = adminManager.GetAdminSection("system.ftpServer/security/requestFiltering", "MACHINE/WEBROOT/APPHOST/Default Web Site")
Set denyUrlSequencesCollection = requestFilteringSection.ChildElements.Item("denyUrlSequences").Collection

Set addElement = denyUrlSequencesCollection.CreateNewElement("add")
addElement.Properties.Item("sequence").Value = "bin"
denyUrlSequencesCollection.AddElement(addElement)

adminManager.CommitChanges()