/Code Review/Basic Command Injection

Basic Command Injection

Simple command injection through unsanitized user input in shell commands.

CRITICALEasy

Vulnerable Codepython

1import os
2
3def check_domain(domain):
4    # Check if domain is reachable
5    result = os.popen(f"nslookup {domain}").read()
6    return result

Understanding the Issue

os.popen() executes commands through the shell, allowing command chaining with ; | && etc. User input should never be interpolated into shell commands.

Command Chaining

Use semicolon to execute additional commands

Malicious Input

domain = "google.com; whoami; id"

Impact

Returns DNS lookup + current user + user ID

Technical Details

Vulnerability Type: OS Command Injection
Severity: CRITICAL
Language: Python
CWE: CWE-78
OWASP: A03:2021 - Injection

Basic Command Injection

Understanding the Issue

How Attackers Exploit This

Command Chaining

Finding the Vulnerability(3 hints)

Technical Details

Basic Command Injection

Understanding the Issue

How Attackers Exploit This

Command Chaining

Finding the Vulnerability(3 hints)

Technical Details