# <add> Element for schemeSettings (Uri Settings)

Adds a scheme setting for a scheme name.

## Syntax

<add
name="http|https"
genericUriParserOptions="DontUnescapePathDotsAndSlashes"
/>


## Attributes and Elements

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

### Attributes

Attribute Description
name The scheme name for which this setting applies. The only supported values are name="http" and name="https".

## {Attribute name} Attribute

Value Description
genericUriParserOptions The parser options for this scheme. The only supported value is genericUriParserOptions= "DontUnescapePathDotsAndSlashes".

None

### Parent Elements

Element Description
<schemeSettings> Element (Uri Settings) Specifies how a Uri will be parsed for specific schemes.

## 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>