Command Injection Prevention

Command injection is a type of attack where an attacker is able to execute arbitrary commands on the host operating system via a vulnerable application. This can lead to unauthorized access, data breaches, and system compromise.

Command Injection: A security vulnerability that allows an attacker to execute arbitrary commands on the host operating system through a vulnerable application.

Command injection typically occurs when an application accepts user input and includes that input in a command that is executed by the system shell. If the application does not properly validate or sanitize this input, an attacker can craft input that alters the command's intended execution.

 
# Vulnerable code example
user_input = "ls; rm -rf /"  # Example of an injection
os.system("bash -c " + user_input)
            

To prevent command injection attacks, consider the following techniques:

• Validate and sanitize all user inputs.
• Use parameterized commands or prepared statements.
• Limit user permissions and access.
• Use least privilege principles for executing commands.
• Employ proper error handling to avoid exposing system information.

# Secure code example
import subprocess

user_input = "some_safe_input"  # Assume this is validated
subprocess.run(["ls", user_input], check=True)  # Safer way to run commands
            

Follow these best practices to enhance security against command injection:

1. Always validate input against a whitelist.
2. Escape shell metacharacters properly.
3. Utilize built-in functions for executing commands (e.g., subprocess in Python).
4. Conduct regular security audits and penetration testing.
5. Stay updated with security patches and updates for all software.