Information Disclosure in Adonisjs with Jwt Tokens
Information Disclosure in Adonisjs with Jwt Tokens
Information disclosure in AdonisJS when using JWT tokens occurs when sensitive data is unintentionally exposed through token payloads, logging, error messages, or token introspection endpoints. JWTs are often used for stateless authentication, but developers sometimes place sensitive or identifying information directly into the token payload. Since JWTs are typically base64-encoded and not encrypted by default (unless using JWE), any data in the payload can be read by an attacker who intercepts the token. This can reveal user identifiers, roles, email addresses, or internal IDs, leading to identity exposure or account enumeration.
In AdonisJS, information disclosure can also arise from inconsistent validation and serialization in API responses. For example, an endpoint might return a full user object that includes fields like id, email, or role when only a subset is necessary. If JWT-based routes fail to enforce proper authorization checks, an attacker can manipulate token claims (such as changing a role claim from user to admin) to access higher-privileged data. Even without modifying tokens, verbose error messages in AdonisJS applications may leak stack traces or internal paths when JWT validation fails, exposing framework or library versions.
AdonisJS applications using the @adonisjs/auth package often rely on the Hash provider for tokens, but misconfigured guards or improper token storage on the client side can lead to leakage. Tokens stored in local storage are accessible via JavaScript, making them vulnerable to cross-site scripting (XSS) attacks, which can result in account takeover and further information disclosure. Additionally, if an AdonisJS application echoes back decoded token contents in logs or debug responses, attackers can harvest sensitive data through log injection or unauthorized debug endpoints.
Real-world attack patterns include intercepting unencrypted JWTs over insecure channels, exploiting verbose error handling to infer valid user identifiers, and manipulating token claims to access unauthorized resources. For instance, an attacker might send a request with a tampered JWT containing an altered sub claim to enumerate other user records if the application does not enforce proper ownership checks. The combination of JWT usage and insufficient data minimization in AdonisJS APIs creates a clear path for information disclosure that can violate privacy regulations and expose sensitive user data.
Jwt Tokens-Specific Remediation in Adonisjs
To mitigate information disclosure risks with JWT tokens in AdonisJS, apply the principle of minimal data exposure in token payloads and enforce strict validation and serialization practices. Avoid storing sensitive or identifying fields such as email, password hashes, or internal IDs directly in the JWT payload. Instead, use opaque tokens or reference tokens where necessary, and rely on server-side session stores for sensitive metadata.
When generating JWTs in AdonisJS, limit the payload to essential claims such as user identifier, role, and expiration. Use the jwt provider from @adonisjs/auth and ensure tokens are signed with a strong algorithm like HS256 or RS256. Below is an example of creating a JWT with a minimal payload:
import { JwtProvider } from '@ioc:Adonis/Addons/Auth'
const jwt = new JwtProvider({
secret: process.env.JWT_SECRET,
expiresIn: '2h',
})
const token = await jwt.generate({
sub: String(user.id), // minimal identifier
role: user.role, // only necessary claims
})
Ensure that API responses do not include sensitive fields. Use serialization layers to filter out properties such as email, password, or createdAt when returning user data. For example, define a serializer that returns only safe fields:
import { DateTime } from 'luxon'
export const userSerializer = (user) => ({
id: user.id,
username: user.username,
role: user.role,
isActive: user.isActive,
// explicitly exclude sensitive fields
})
Additionally, configure AdonisJS error handlers to avoid exposing stack traces or internal paths in production. Use generic error messages for authentication failures and ensure that JWT validation errors do not reveal whether a token was malformed, expired, or associated with a non-existent user. Enforce HTTPS to prevent token interception and consider using the HttpOnly and Secure flags when storing tokens in cookies, reducing exposure via XSS.
For applications using the GitHub Action integration, you can automatically scan for information disclosure patterns in API routes that handle JWTs. The Pro plan’s continuous monitoring can alert you when new endpoints introduce risky data exposure, helping you maintain compliance with frameworks such as OWASP API Top 10 and GDPR.