Template Injection
Server-Side Template Injection (SSTI) is attackers injecting template syntax into the rendering context, executing arbitrary code in the server-side template engine.
Purpose
To understand SSTI caused by user input reaching template rendering and its defenses; a common vulnerability in Jinja2/Freemarker and similar.
Mechanism
The program renders user input as a template via template.render(user_input); the attacker enters {{7*7}} or {{config}} to execute expressions or leak objects. Defenses: separate templates from data, sandboxing, safe rendering.
Use cases
- Jinja2 SSTI
- Freemarker security
- Template engine audit