Modification of encoded or escaped URLs

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WebSEAL modifies and rewrites the URL references in outgoing responses to ensure that subsequent requests are sent through WebSEAL.

WebSEAL rewrites each URL in its original form with the URI encoding or slash escaping. If WebSEAL encounters special character encoding, it replaces the HTML code with the special character that the code represents.

The following table describes the URI encoding types that WebSEAL filters during this process.

Table 1. Filtered encoding typesWebSEAL filters the following encoding types.
Encoding type	Example of encoded URL
Ampersand encoded	`HTTP://host:port/path?V1=D1&V2=D2`
Ampersand - hex encoded	`HTTP://host:port/`
Ampersand - dec encoded	`HTTP:99host:port9`
Backslash encoded	`HTTP:\/\/host:port\/`
Percent hex encoded	`HTTP%3A%2F%2Fhost%3Aport%2F`

Example: Filtering of URLs

WebSEAL server: www.webseal.com

The following junction was created:

server task webseal-server create -tcp -h www.example.com /jct

The HTML before the WebSEAL filtering process:

<HTML>
<BODY>
<A HREF="http%3A%2F%2Fwww.example.com%2Findex.html">index.html</A>
<A HREF="http:\/\/www.example.com\/page2.html">page2.html</A>
<A HREF="http://www.example.com/page3.html">page3.html</A>
<A HREF="http&#x3A;&#x2F;&#x2F;www.example.com&#x2F;page4.htm">page4.html</A>
</BODY>
</HTML>

HTML after the WebSEAL filtering process with the configuration item [script-filtering] rewrite-absolute-with-absolute set to no:

<HTML>
<BODY>
<A HREF="%2Fjct%2Findex.html">index.html</A>
<A HREF="\/jct\/page2.html">page2.html</A>
<A HREF="/jct/page3.html">page3.html</A>
<A HREF="&#x2F;jct&#x2F;page4.htm">page4.html</A>
</BODY>
</HTML>

HTML after the WebSEAL filtering process with the configuration item [script-filtering] rewrite-absolute-with-absolute set to yes:

<HTML>
<BODY>
<A HREF="http%3A%2F%2Fwww.webseal.com%2Fjct%2Findex.html">index.html</A>
<A HREF="http:\/\/www.webseal.com\/jct\/page2.html">page2.html</A>
<A HREF="http://www.webseal.com/jct/page3.html">page3.html</A>
<A HREF="http&#x3A;&#x2F;&#x2F;www.webseal.com&#x2F;jct&#x2F;page4.htm">
page4.html</A>
</BODY>
</HTML>