Fix JWT Vulnerabilities (Weak Signing, None Algo) in Hapi

Broken JWT implementations in Hapi are a goldmine for attackers. Using the 'none' algorithm allows an attacker to forge tokens by simply removing the signature, while weak secrets succumb to offline brute-force in seconds. To secure Hapi, you must enforce strict algorithm pinning and high-entropy secrets within your hapi-auth-jwt2 strategy.

The Vulnerable Pattern

await server.register(require('hapi-auth-jwt2'));
server.auth.strategy('jwt', 'jwt', {
  key: 'super-secret', // WEAK: Easily brute-forced
  validate: basicValidation,
  verifyOptions: {
    algorithms: ['HS256', 'none'] // FATAL: Allows 'none' algorithm attack
  }
});

The Secure Implementation

The secure implementation mitigates two primary vectors. First, by removing 'none' from the algorithms array and pinning it to 'HS256', the library will reject any token where the header specifies an insecure or mismatched algorithm. Second, replacing the hardcoded 'super-secret' with a high-entropy key sourced from environment variables prevents signature forgery via dictionary attacks. In Hapi, the hapi-auth-jwt2 plugin must be explicitly locked down to prevent it from defaulting to permissive verification modes.

const Crypto = require('crypto');
// Ensure JWT_SECRET is a high-entropy string from env
const secureKey = process.env.JWT_SECRET || Crypto.randomBytes(32).toString('hex');
await server.register(require(‘hapi-auth-jwt2’));
server.auth.strategy(‘jwt’, ‘jwt’, {
key: secureKey,
validate: strictValidation,
verifyOptions: {
algorithms: [‘HS256’], // FIX: Explicitly pin to a secure algorithm
allowAnySignature: false // FIX: Ensure signature verification is mandatory
}
});