# <schemeSettings> Element (Uri Settings)

Specifies how a Uri will be parsed for specific schemes.

<configuration>
<uri>
<schemeSettings>

## Syntax

<schemeSettings>
</schemeSettings>


## Attributes and Elements

The following sections describe attributes, child elements, and parent elements.

None

### Child Elements

Element Description
add Adds a scheme setting for a scheme name.
clear Clears all existing scheme settings.
remove Removes a scheme setting for a scheme name.

### Parent Elements

Element Description
uri Contains settings that specify how the .NET Framework handles web addresses expressed using uniform resource identifiers (URIs).

## Remarks

By default, the System.Uri class un-escapes percent encoded path delimiters before executing path compression. This was implemented as a security mechanism against attacks like the following:

http://www.contoso.com/..%2F..%2F/Windows/System32/cmd.exe?/c+dir+c:\

If this URI gets passed down to modules not handling percent encoded characters correctly, it could result in the following command being executed by the server:

c:\Windows\System32\cmd.exe /c dir c:\

For this reason, System.Uri class first un-escapes path delimiters and then applies path compression. The result of passing the malicious URL above to System.Uri class constructor results in the following URI:

http://www.microsoft.com/Windows/System32/cmd.exe?/c+dir+c:\

This default behavior can be modified to not un-escape percent encoded path delimiters using the schemeSettings configuration option for a specific scheme.

## Configuration Files

This element can be used in the application configuration file or the machine configuration file (Machine.config).

## Example

The following example shows a configuration used by the Uri class to support not escaping percent-encoded path delimiters for the http scheme.

<configuration>
<uri>
<schemeSettings>
<add name="http" genericUriParserOptions="DontUnescapePathDotsAndSlashes"/>
</schemeSettings>
</uri>
</configuration>


Namespace System
Schema Name
Validation File
Can be Empty