What is Use of Single-factor Authentication (CWE-308)?

TL;DR: Use of Single-factor Authentication (CWE-308) is a critical vulnerability that occurs when an application uses only one factor, such as a password, to authenticate users. It can be prevented by implementing multi-factor authentication, using secure password storage, and regularly updating dependencies.

At-a-Glance Table

What is Use of Single-factor Authentication?

Use of Single-factor Authentication (CWE-308) is a type of authentication vulnerability that occurs when an application uses only one factor, such as a password, to authenticate users. As defined by the MITRE Corporation under CWE-308, and classified by the OWASP Foundation under A07:2025 - Authentication Failures, this vulnerability can lead to bypassing protection mechanisms.

Quick Summary

Use of Single-factor Authentication (CWE-308) is a critical vulnerability that occurs when an application uses only one factor, such as a password, to authenticate users. This can result in unauthorized access to sensitive data and systems. To prevent this vulnerability, implement multi-factor authentication, use secure password storage, and regularly update dependencies.

Jump to: Quick Summary · Use of Single-factor Authentication Overview · How Use of Single-factor Authentication Works · Business Impact of Use of Single-factor Authentication · Use of Single-factor Authentication Attack Scenario · How to Detect Use of Single-factor Authentication · How to Fix Use of Single-factor Authentication · Framework-Specific Fixes for Use of Single-factor Authentication · How to Ask AI to Check Your Code for Use of Single-factor Authentication · Use of Single-factor Authentication Best Practices Checklist · Use of Single-factor Authentication FAQ · Vulnerabilities Related to Use of Single-factor Authentication · References · Scan Your Own Site

Use of Single-factor Authentication Overview

What

Use of Single-factor Authentication (CWE-308) is a type of authentication vulnerability that occurs when an application uses only one factor, such as a password, to authenticate users.

Why it matters

If the secret in a single-factor authentication scheme gets compromised, full authentication is possible, leading to bypassing protection mechanisms. This can result in unauthorized access to sensitive data and systems.

Where it occurs

This vulnerability can occur in any application that uses single-factor authentication, including web applications, APIs, and mobile apps.

Who is affected

Any user who relies on single-factor authentication to access an application may be affected by this vulnerability.

Who is NOT affected

Applications that use multi-factor authentication or other secure authentication methods are not affected by this vulnerability.

How Use of Single-factor Authentication Works

Root Cause

The root cause of this vulnerability is the use of single-factor authentication, which relies on a secret being known to both the user and the application.

Attack Flow

1. An attacker compromises the secret used in the single-factor authentication scheme.
2. The attacker uses the compromised secret to authenticate with the application.
3. The application grants access to the attacker without verifying their identity.

Prerequisites to Exploit

• The secret must be known to both the user and the attacker.
• The attacker must have access to the compromised secret.

Vulnerable Code

import requests

def authenticate(username, password):
    response = requests.post('https://example.com/login', data={'username': username, 'password': password})
    if response.status_code == 200:
        return True
    else:
        return False

This code uses a single-factor authentication scheme that relies on the user’s password being known to both the user and the application.

Secure Code

import requests
from cryptography.fernet import Fernet

def authenticate(username, password):
    # Generate a secret key using Fernet
    secret_key = Fernet.generate_key()
    
    # Encrypt the password using the secret key
    encrypted_password = Fernet(secret_key).encrypt(password.encode())
    
    response = requests.post('https://example.com/login', data={'username': username, 'encrypted_password': encrypted_password})
    if response.status_code == 200:
        return True
    else:
        return False

This code uses a multi-factor authentication scheme that relies on the user’s password being encrypted using a secret key.

Business Impact of Use of Single-factor Authentication

Confidentiality

If the secret in a single-factor authentication scheme gets compromised, full authentication is possible, leading to unauthorized access to sensitive data and systems. This can result in financial losses, reputational damage, and compliance issues.

Integrity

The compromise of the secret used in a single-factor authentication scheme can also lead to unauthorized changes to sensitive data and systems.

Availability

The use of single-factor authentication can also lead to downtime and system unavailability due to the need for frequent password resets and account lockouts.

Use of Single-factor Authentication Attack Scenario

1. An attacker compromises the secret used in a single-factor authentication scheme.
2. The attacker uses the compromised secret to authenticate with an application.
3. The application grants access to the attacker without verifying their identity.
4. The attacker accesses sensitive data and systems, leading to unauthorized changes and financial losses.

How to Detect Use of Single-factor Authentication

Manual Testing

• Review your code for potential vulnerabilities in single-factor authentication schemes.
• Test your application’s login functionality using tools like Burp Suite or ZAP.

Automated Scanners (SAST / DAST)

• Use automated scanning tools like PenScan, Veracode, or Checkmarx to detect potential vulnerabilities in single-factor authentication schemes.
• Note that static analysis may not catch all instances of this vulnerability, as dynamic testing is required to verify the behavior of the application.

PenScan Detection

PenScan’s automated scanning engines actively test for this vulnerability and provide recommendations for remediation.

False Positive Guidance

When reviewing your scan results, be sure to check for false positives. For example, if a scanner flags a login page as vulnerable due to its use of single-factor authentication, but the application also uses multi-factor authentication in certain situations, it may not be a true vulnerability.

How to Fix Use of Single-factor Authentication

• Implement multi-factor authentication using secure password storage and encryption.
• Regularly update dependencies to prevent this vulnerability.
• Consider implementing additional security measures, such as two-factor authentication or biometric authentication.

Framework-Specific Fixes for Use of Single-factor Authentication

C

#include <stdio.h>
#include <stdlib.h>

int main() {
    char username[256], password[256];
    printf("Enter username: ");
    fgets(username, 256, stdin);
    printf("Enter password: ");
    fgets(password, 256, stdin);

    // Encrypt the password using a secret key
    char encrypted_password[256];
    // ...

    // Authenticate with the server
    int response = send_request(username, encrypted_password);
    if (response == 200) {
        printf("Authentication successful\n");
    } else {
        printf("Authentication failed\n");
    }

    return 0;
}

Java

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter username: ");
        String username = scanner.nextLine();
        System.out.print("Enter password: ");
        String password = scanner.nextLine();

        // Encrypt the password using a secret key
        byte[] encrypted_password = encrypt(password);

        // Authenticate with the server
        int response = send_request(username, encrypted_password);
        if (response == 200) {
            System.out.println("Authentication successful");
        } else {
            System.out.println("Authentication failed");
        }
    }

    private static byte[] encrypt(String password) {
        // ...
    }

    private static int send_request(String username, byte[] encrypted_password) {
        // ...
    }
}

How to Ask AI to Check Your Code for Use of Single-factor Authentication

You can use AI-powered coding assistants like GitHub Copilot or Kite to review your code for potential vulnerabilities in single-factor authentication schemes. Simply paste the following prompt into the assistant:

“Review the following [language] code block for potential CWE-308 Use of Single-factor Authentication vulnerabilities and rewrite it using multi-factor authentication with secure password storage and encryption: [paste code here]”

Use of Single-factor Authentication Best Practices Checklist

✅ Implement multi-factor authentication using secure password storage and encryption. ✅ Regularly update dependencies to prevent this vulnerability. ✅ Consider implementing additional security measures, such as two-factor authentication or biometric authentication.

Use of Single-factor Authentication FAQ

How do I define Use of Single-factor Authentication?

Use of Single-factor Authentication (CWE-308) is a type of authentication vulnerability that occurs when an application uses only one factor, such as a password, to authenticate users.

What are the consequences of using single-factor authentication?

If the secret in a single-factor authentication scheme gets compromised, full authentication is possible, leading to bypassing protection mechanisms.

How can I detect Use of Single-factor Authentication in my application?

You can use PenScan’s automated scanning engines or manually review your code for potential vulnerabilities.

What are some best practices for preventing Use of Single-factor Authentication?

Implement multi-factor authentication, use secure password storage, and regularly update dependencies to prevent this vulnerability.

Can AI help me identify and fix Use of Single-factor Authentication in my application?

Yes, you can use AI-powered coding assistants to review your code for potential vulnerabilities and provide recommendations for remediation.

What are some related weaknesses to Use of Single-factor Authentication?

CWE-1390 (Weak Authentication) and CWE-654 (Reliance on a Single Factor in a Security Decision) are related weaknesses that can lead to similar consequences.

How do I prevent Use of Single-factor Authentication in my application?

Implement multi-factor authentication, use secure password storage, and regularly update dependencies to prevent this vulnerability.

Vulnerabilities Related to Use of Single-factor Authentication

References

• MITRE CWE-308
• OWASP A07:2025 - Authentication Failures
• CAPEC-16, CAPEC-49, CAPEC-509, CAPEC-55, CAPEC-555, CAPEC-560, CAPEC-561, CAPEC-565, CAPEC-600, CAPEC-644, CAPEC-645, CAPEC-652, CAPEC-653, CAPEC-70
• NVD

Scan Your Own Site

Manual code review catches what you know to look for. An automated scan catches what you didn’t. Scan your own website using PenScan to find Use of Single-factor Authentication and other risks before an attacker does.