how to secure against Server Side Template Injection (SSTI) Check ?

how to secure against : Server Side Template Injection (SSTI) Check ?


Title: Protecting Against Server Side Template Injection (SSTI) Attacks – Safeguarding From Human Exploit and Hackers


Server Side Template Injection (SSTI) is a critical vulnerability that exposes web applications to severe breaches, enabling attackers to execute arbitrary code or even gain control over the entire system. This article explores the nature of SSTI attacks, the ways in which both human error and hackers can exploit them, and lists some proactive measures to avoid such attacks.

Understanding Server Side Template Injection (SSTI)

Server Side Template Injection occurs when an application incorporates user-submitted data into a server-side template, without proper sanitization or validation. This allows an attacker to manipulate the template engine to execute code, leading to unauthorized access and data exposure.

Exploitation by Human Error

Often, vulnerabilities arise due to human mistakes, such as developers failing to validate or sanitize user input before incorporating it into a template. Without proper handling, attackers can exploit this negligence to inject malicious code.

Exploitation by Hackers

On the other hand, malicious hackers actively search for applications with SSTI vulnerabilities. They employ techniques like payload injection, where malicious code is injected into user input fields, leading to code execution on the server side. Once compromised, hackers can elevate privileges, exfiltrate sensitive data, or even launch further attacks across the network.

Preventing SSTI Attacks

To minimize the risk of SSTI attacks, consider the following preventive measures:

1. Input Validation: Implement strict input validation and sanitization techniques to ensure that user input is properly handled before use in templates. Apply input filters and restrict the use of potentially dangerous characters.

2. Contextual Output Encoding: Employ appropriate encoding techniques based on the context in which the data is being rendered. This ensures that any user-submitted content is displayed securely, preventing the execution of malicious code.

3. Template Engine Hardening: Familiarize yourself with the template engine's documentation and best practices. Disable dangerous or unnecessary features, such as inline evaluation of expressions or dynamic template evaluation.

4. Regular Patching and Updates: Stay up to date with security patches and updates for both the web application framework and the template engine being used. These updates often include security fixes that address known vulnerabilities.


Server Side Template Injection poses a significant threat to web application security, with both human error and hackers capable of exploiting it. By implementing robust input validation, contextual output encoding, template engine hardening, and regularly patching software, you can significantly reduce the chances of SSTI attacks. Staying vigilant, continuously educating developers, and performing regular security audits are essential steps towards safeguarding your applications from these vulnerabilities.