Fix Command Injection in Masonite
Command injection in Masonite controllers allows attackers to execute arbitrary system commands by exploiting sinks that interface with the OS shell. This typically happens when 'request.input()' data is concatenated directly into functions like 'os.system' or 'subprocess.Popen' with 'shell=True'.
The Vulnerable Pattern
from masonite.controllers import Controller from masonite.request import Request import os
class BackupController(Controller): def create(self, request: Request): filename = request.input(‘filename’) # VULNERABLE: Direct concatenation into shell command os.system(f”tar -cvf backups/{filename}.tar /tmp/data”) return “Backup started”
The Secure Implementation
The vulnerable code uses string interpolation to build a shell command, allowing an attacker to inject subcommands via metacharacters like ';' or '&&'. The secure implementation mitigates this by using the 'subprocess' module with an argument list. This avoids spawning a shell ('shell=False' by default), ensuring that the input is treated strictly as a filename argument rather than executable code. Additionally, regex whitelisting is applied to restrict the input character set.
from masonite.controllers import Controller
from masonite.request import Request
import subprocess
import re
class BackupController(Controller):
def create(self, request: Request):
filename = request.input(‘filename’)
# 1. Validate input format
if not re.match(r'^[a-zA-Z0-9_\-]+$', filename):
return "Invalid filename", 400
# 2. Use subprocess with a list (shell=False) to prevent command injection
subprocess.run(["tar", "-cvf", f"backups/{filename}.tar", "/tmp/data"], check=True)
return "Backup completed safely"</code></pre>
Your Masonite API
might be exposed to Command Injection
74% of Masonite apps fail this check. Hackers use automated scanners to find this specific flaw. Check your codebase before they do.
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