Vendure vulnerable to timing attack that enables user enumeration in NativeAuthenticationStrategy

Summary

The NativeAuthenticationStrategy.authenticate() method is vulnerable to a timing attack that allows attackers to enumerate valid usernames (email addresses).

Details

In packages/core/src/config/auth/native-authentication-strategy.ts, the authenticate method returns immediately if a user is not found:

const user = await this.userService.getUserByEmailAddress(ctx, data.username);
if (!user) {
    return false; // Instant return (~1-5ms)
}
const passwordMatch = await this.verifyUserPassword(ctx, user.id, data.password);
// Password check takes ~200-400ms with bcrypt (12 rounds)

The significant timing difference (~200-400ms for bcrypt vs ~1-5ms for DB miss) allows attackers to reliably distinguish between existing and non-existing accounts.

Impact

• Attackers can enumerate valid user accounts
• Enables targeted brute-force or phishing attacks
• Information disclosure (account existence)

Recommended Fix

Perform a dummy bcrypt check when user is not found to ensure consistent response times.