5.1 SSTI Overview

SSTI in a nutshell

Server-Side Template Injection is an attack where a malicious payload is injected into a template which is then executed server-side.

What are Templates ?

Templates allow to pre-populate dynamic data from the server into a web page. Web pages coming from web templates can structure the component of web pages in such a way that can be modified independently of each other. Templates are commonly used for:

• Displaying information about users (username, bio...), products, companies.
• Sending bulk emails.
• Displaying a gallery of photos or videos.

Example:

Hello {{user.name}}

Example of vulnerable Angular Template

A malicious user can inject malicious code from unknown origin which will be executed in potentialUserInput.

Source: https://snyk.io/blog/angular-security-best-practices/