7 Best Ways to Prevent JWT Attacks in TypeScript ERP

Introduction

JSON Web Tokens (JWT) are widely used for authentication and authorization in modern applications, including TypeScript-based ERP systems. While JWTs provide a stateless and scalable authentication mechanism, misconfigurations and poor implementation practices can expose ERP systems to severe security vulnerabilities.

Attackers often exploit insecure JWT handling, leading to:
✅ Token forgery and tampering
✅ Signature bypassing
✅ Algorithm attacks
✅ Token leakage and replay attacks

In this guide, we’ll explore common JWT attacks in TypeScript ERP applications and 7 best practices to prevent them with practical coding examples.

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Common JWT Attacks in TypeScript ERP Systems

Understanding JWT attacks is crucial for preventing security breaches. Here are some of the most common attack vectors:

1️⃣ JWT Signature Forgery (None Algorithm Attack)

A JWT should always be signed with a secure cryptographic algorithm. However, if an application incorrectly allows “none” as an algorithm, attackers can forge JWTs without needing a secret key.

❌ Vulnerable Code Example

import jwt from 'jsonwebtoken';

const token = jwt.sign({ user: 'admin' }, '', { algorithm: 'none' }); // Vulnerable
console.log(token);

An attacker can modify the JWT payload and set "alg": "none", making the server accept unsigned JWTs.

2️⃣ Weak Signing Key Exploitation

Using a weak or guessable secret key makes JWTs easy to forge.

❌ Example of an Insecure Secret Key

const secretKey = '12345'; // Too weak

An attacker can brute-force the secret key and generate valid JWTs.

3️⃣ Key Confusion Attack

If a system accepts both HMAC and RSA signatures interchangeably, attackers can exploit this by using an HMAC-signed JWT but verifying it with an RSA public key.

4️⃣ Expired Token Replay Attack

JWTs without proper expiration checks can be reused, allowing attackers to replay expired tokens to gain unauthorized access.

5️⃣ Token Storage Vulnerabilities

Storing JWTs in localStorage or sessionStorage exposes them to Cross-Site Scripting (XSS) attacks.

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7 Best Ways to Prevent JWT Attacks in TypeScript

Now that we’ve covered common JWT vulnerabilities, let’s go through the best security practices to mitigate these risks.

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1️⃣ Always Use a Strong Secret Key

Using a long, randomly generated secret key helps prevent brute-force attacks.

✅ Example: Secure Key Generation

import crypto from 'crypto';

const secretKey = crypto.randomBytes(64).toString('hex'); // Secure key

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2️⃣ Enforce a Secure Signing Algorithm

Always use strong algorithms like HS256, RS256, or ES256 for JWT signing.

✅ Example: Secure JWT Signing

import jwt from 'jsonwebtoken';

const payload = { user: 'admin' };
const token = jwt.sign(payload, process.env.SECRET_KEY, { algorithm: 'HS256' });

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3️⃣ Implement Token Expiry and Refresh Mechanism

Set a short expiration time and use refresh tokens securely.

✅ Example: Secure Token Expiration

const token = jwt.sign({ user: 'admin' }, process.env.SECRET_KEY, { expiresIn: '15m' });

For refresh tokens, store them securely and rotate them after each use.

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4️⃣ Store Tokens Securely (Avoid LocalStorage)

Never store JWTs in localStorage. Instead, use httpOnly cookies.

✅ Example: Setting Secure Cookies

res.cookie('jwt', token, { httpOnly: true, secure: true, sameSite: 'Strict' });

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5️⃣ Implement a Token Revocation Mechanism

Invalidate compromised tokens by maintaining a deny list.

✅ Example: Token Blacklist

const blacklistedTokens = new Set<string>();

function isTokenRevoked(token: string): boolean {
    return blacklistedTokens.has(token);
}

// Revoke a token
blacklistedTokens.add(compromisedToken);

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6️⃣ Validate JWTs Properly

Ensure that JWTs are properly validated before granting access.

✅ Example: Secure JWT Verification

function verifyToken(token: string): object | null {
    try {
        return jwt.verify(token, process.env.SECRET_KEY);
    } catch (error) {
        return null;
    }
}

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7️⃣ Conduct Regular Security Audits

Perform security testing to identify JWT vulnerabilities.

🔹 Try our Website Vulnerability Scanner

📷 Screenshot of Free Tool Webpage

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📷 Screenshot of Website Vulnerability Assessment Report to check Website Vulnerability

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Conclusion

By following these 7 best security practices, you can protect your TypeScript-based ERP system from JWT attacks and prevent unauthorized access.

For more security guides, check out our previous posts:

• How to Prevent OAuth Misconfiguration in TypeScript
• How to Prevent NoSQL Injection in TypeScript
• React.js Apps Vulnerability Assessments
• More Cybersecurity Articles

🔐 Secure your JWT implementation today and safeguard your ERP system from cyber threats!

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