# Welcomely — Server-Side Template Injection (lab)

> Welcomely builds a personalized welcome page from the name you enter — by pasting it straight into a server-side template.

Canonical: https://codelivly.com/labs/ssti

| | |
|---|---|
| Type | Web |
| Difficulty | Advanced |
| Points | 450 |
| Session length | 30 min |
| Completions | 12 |

Welcomely builds a personalized welcome page from the name you enter — by pasting it straight into a server-side template. Templates don't just insert text, they evaluate expressions, so the right "name" runs code on the server. Break out of the template and read the flag from the server's environment.

## Objective

Learn server-side template injection: when user input is placed into a template that the server then renders, the template engine evaluates the input as an expression — a short path from "personalized greeting" to arbitrary code execution on the server.

## Tasks

1. Generate a greeting
2. Test for evaluation
3. Reach the object model
4. Read the environment
5. Capture the flag

## Related

- [All labs](https://codelivly.com/practice?type=lab)