Description

Detects insecure HTTP listener configurations in C# applications where wildcards are used in prefix settings. This vulnerability could allow an attacker to access the HTTP listener on unintended network interfaces or ports, potentially exposing sensitive functionality to unauthorized users.

Detection Strategy

• Check if the System.Net library is imported in the C# code

• Look for method calls ending with '.Prefixes.Add'

• Verify if the prefix value contains unsafe patterns (like wildcards)

• Confirm the prefix is being added to an HttpListener object

• Report a vulnerability when all these conditions are met in the code

Vulnerable code example

using System.Net;

public class VulnerableListener {
    public void StartListener() {
        HttpListener listener = new HttpListener();
        
        // Vulnerable: Using wildcard (*) allows binding to all interfaces, potentially exposing to unauthorized networks
        listener.Prefixes.Add("http://*:8080");...

✅ Secure code example

using System.Net;

public class SecureListener {
    public void StartListener() {
        HttpListener listener = new HttpListener();
        
        // Secure: Bind to specific localhost interface to prevent external access
        listener.Prefixes.Add("http://localhost:8080/");...