Securing Push Notification Services

Securing Push Notification Services

11/12/2024

Platforms like OneSignal, WonderPush, and similar applications are popular for enabling push notification services. However, development teams integrating these platforms into their applications risk exposure to token-based attacks.

In this article, we explore the methods attackers use in token-based attacks and provide recommendations to mitigate such risks.

Token Security Challenges

Push notification platforms rely on unique device identifiers and API keys (tokens) to deliver notifications. These tokens may include:

1.User Auth Tokens : Used to differentiate users.

2.REST API Key : Private keys used to send notifications from the server.

Attackers often intercept these keys by analyzing the API calls of mobile or web applications. Common attack steps include:

1.Application Analysis: Attackers download the app and perform reverse engineering.

2.Network Traffic Interception: Analyzing communication between the app and the notification platform’s servers to extract tokens.

3.API Key Exploitation: Using stolen tokens to send fake notifications, mislead users, or distribute malicious content.

Causes of Token Security Issues

1.Hardcoded Keys: Developers embed REST API Keys or other credentials directly in the mobile application code.

2.Insufficient Encryption: Weak encryption between the app and server enables attackers to eavesdrop on traffic and steal tokens.

3.Inadequate Access Control: Lack of user-based access control in API calls allows attackers to misuse stolen tokens for unauthorized actions.

Recommendations for Enhancing Token Security

1. Avoid Hardcoding

Issue: Hardcoded credentials in the app are vulnerable to reverse engineering.

Solution: Store sensitive information on the server side and only send dynamic data (e.g., temporary tokens) to the app.

2. Use HTTPS

Issue: Communication over unencrypted HTTP can be intercepted.

Solution: Ensure all communication between the app and platforms like OneSignal is over HTTPS, with properly configured SSL/TLS certificates.

3. Adopt Dynamic Tokens

Issue: Long-lived tokens increase misuse risk.

Solution: Implement short-lived tokens that are regularly refreshed (e.g., JSON Web Tokens - JWT). If compromised, these tokens quickly become invalid.

4. Implement API Access Control

Issue: Stolen tokens can be used broadly for unauthorized API calls.

Solution: Add user-based access control to the token verification process, ensuring tokens are tied to specific user actions.

5. Obfuscate Application Code

Issue: Reverse engineering of app code reveals sensitive data.

Solution: Use code obfuscation tools like ProGuard or R8 for Android to make analysis more difficult.

6. Apply Rate Limiting

Issue: Attackers can use stolen tokens to make excessive API calls.

Solution: Introduce rate limiting on API endpoints (e.g., a maximum number of requests per second from a single IP) to restrict malicious activity.

7. Enable Security Logging and Monitoring

Issue: Attacks may go unnoticed.

Solution: Deploy comprehensive logging and monitoring systems to detect anomalies in API usage. For example, if a token is used excessively in a short time, automatically revoke it.