Microservices offer scalability and flexibility but increase the attack surface. Securing Spring-based microservices requires a layered approach covering client, API gateway, services, data, and infrastructure.
1️⃣ Authentication & Authorization
Example: Logging in with username/password or OAuth token.
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Authorization – Determines what a verified user can access (roles, permissions).
Example: Admins can access /admin/**, users cannot.
Authentication Approaches in Spring
Authentication verifies who a user is. Spring provides multiple ways to implement it depending on your needs: stateless, session-based, enterprise directories, or external providers.
1) OAuth 2.0 / OpenID Connect
Definition
OAuth 2.0 and OpenID Connect (OIDC) are standard protocols for secure authentication and authorization.
OAuth 2.0 / OIDC is a token-based authentication mechanism that delegates login to an Identity Provider (IdP).
It supports single sign-on (SSO) and is widely used in modern microservices and enterprise systems.
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OAuth 2.0 → An authorization protocol that lets applications access resources on behalf of a user using an access token, without exposing the user’s password.
OIDC → An authentication layer on top of OAuth 2.0, which issues an ID token (JWT) containing user identity details (e.g., name, email, roles).
👉 Together, they enable secure login + API access for modern applications and microservices.
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Example IdPs: Keycloak, Okta, Auth0, AWS Cognito, Azure AD
Token Type: Usually JWT (includes user identity, roles, and claims)
How It Works (Step by Step)
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Client (e.g., Web App or Mobile App) redirects the user to the IdP login page.
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User logs in with username/password (or social login like Google, GitHub, etc.).
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IdP authenticates the user and issues:
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The client sends the token in API requests:
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The Resource Server (Spring Boot microservice) receives the request and validates the token:
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If valid → the request is authenticated and authorized.
Spring Example: Resource Server
This configuration runs in your Spring Boot microservice to validate tokens issued by the IdP:
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Ensures requests contain a valid JWT token.
Extracts roles/claims from JWT (e.g., roles: ADMIN).
Applies authorization rules based on those roles.
Spring Example: Client App (OAuth2 Login)
If your Spring Boot app acts as a frontend or client, configure OAuth2 login like this:
application.yml
Java Config
What this code does:
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Redirects users to the IdP login page.
After successful login, retrieves the tokens and sets up the session.
OAuth 2.0 vs OIDC (Quick Difference)
Feature | OAuth 2.0 (Authorization) | OpenID Connect (Authentication) |
Purpose | API access on behalf of a user | Identify the user (who they are) |
Tokens | Access Token | Access Token + ID Token |
Focus | “What can this app do?” | “Who is the user?” |
Use Case | Securing APIs | Login / Single Sign-On (SSO) |
Use Cases
👉 Together, OAuth 2.0 and OIDC provide centralized authentication + secure authorization across microservices and applications.
Real-World Example
Logging into a banking app using your Google account via OIDC:
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You click “Login with Google.”
Google authenticates you and issues a token.
The banking app’s backend validates the token → grants you secure access to your account.
2) JWT (Stateless Token Authentication)
Definition
A JSON Web Token (JWT) is a compact, URL-safe token used for authentication and authorization. It is stateless — all necessary information (user identity, roles, expiry) is inside the token itself, so the server doesn’t need to store session state.
JWT is structured as: <Header>.<Payload>.<Signature>
Header (metadata)
How It Works (Step by Step)
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User logs in with credentials (e.g., username + password).
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Server validates credentials and issues a JWT signed with a secret/private key.
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The client stores the JWT (in localStorage, sessionStorage, or cookies).
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For each API request, the client sends the token in the header:
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The server validates the JWT by checking:
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Signature → Was it signed by us?
Expiry → Is the token still valid?
Claims → Does the user have required roles/permissions?
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If valid → the request is authenticated and authorized.
Advantages
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Stateless → No need to store session in DB or memory.
Scalable → Works well with microservices and distributed systems.
Lightweight → Compact and can be passed in headers, cookies, or URLs.
Custom claims → Can include roles, permissions, and other user data.
Limitations
-
Tokens can’t be revoked easily (once issued, they’re valid until expiry).
Must be sent over HTTPS (to prevent token theft).
Bigger tokens (with many claims) → increase request size.
Spring Example: Creating a JWT
What this does:
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Builds a JWT with username + roles.
Sets issue & expiry time.
Signs with HS256 algorithm and a secret key.
Spring Example: Validating JWT
What this does:
Real-World Analogy
Think of JWT as an airline boarding pass:
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The pass contains your name, flight number, seat, and expiry (like claims in JWT).
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It’s signed and issued by the airline (like the server signing JWT).
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You don’t need to check in again for every security gate — just show the boarding pass (like sending JWT in every request).
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Security simply validates the signature and expiry before letting you through.
Use Cases
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Stateless APIs → REST APIs in Spring Boot, no session state needed.
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Microservices → Each service validates JWT independently.
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Mobile apps → Token stored locally, sent with every request.
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API Gateway Authentication → Gateway validates JWT before routing requests.
👉 JWT is best suited for scalable, stateless microservices, where storing session state in the backend is not practical.
3) Basic Authentication
Definition
Basic Authentication is a simple authentication mechanism where the username and password are sent with each HTTP request, encoded in Base64.
- Credentials are passed in the Authorization header:
Authorization: Basic base64(username:password) - Since Base64 is not encryption, it must always be used with HTTPS to ensure security.
How It Works (Step by Step)
- The client sends an HTTP request with a header:
Authorization: Basic dXNlcjpwYXNzd29yZA==
(user:password encoded in Base64). - The server decodes the credentials.
- The server verifies the username/password against its user store (e.g., in-memory, database, LDAP).
- If valid → request is authenticated.
- If invalid → the server responds with 401 Unauthorized and a WWW-Authenticate header prompting for credentials.
Spring Example
http
.authorizeHttpRequests()
.anyRequest().authenticated()
.and()
.httpBasic();
What this does:
- Requires authentication for all requests.
- Uses Basic Authentication (credentials in header).
- Spring Security automatically handles the challenge (401 Unauthorized) if credentials are missing or invalid.
Advantages
- Simple to configure and implement.
- Stateless (no session storage required).
- Useful for quick testing or internal APIs.
Limitations
- Credentials sent with every request → higher risk if not over HTTPS.
- Base64 encoding ≠ encryption (credentials can be easily decoded).
- Not suitable for public APIs or large-scale production systems.
- No built-in token refresh or role/claim-based security like JWT or OAuth2.
Real-World Analogy
Think of Basic Auth like a guest list at a party:
- Every time you enter a room, you show your name + password written on a slip.
- The slip itself is not secure (anyone who sees it can copy it).
- But if the party is held inside a secure building (HTTPS), it works fine.
Use Cases
- Quick prototyping or proof-of-concept apps (Not for production)
- Internal services or tools running inside a secured network.
- Testing APIs with tools like Postman or curl.
👉 Basic Authentication is fine for simple, internal, or low-risk services, but for production and internet-facing systems, JWT or OAuth2/OIDC is recommended.
4) LDAP Authentication
Definition
LDAP (Lightweight Directory Access Protocol) is a protocol used to access and manage directory information services such as Active Directory or OpenLDAP.
In authentication, it verifies a user’s credentials against records in the LDAP server and returns attributes like groups/roles, which are mapped to Spring Security authorities.
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Used in enterprises for centralized authentication and authorization.
Common directory services: Active Directory (AD), OpenLDAP.
How It Works (Step by Step)
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A user tries to log in with username + password.
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The Spring Boot application forwards the credentials to the LDAP server.
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The LDAP server checks the password against its stored records.
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If authentication succeeds, LDAP returns user attributes (e.g., groups/roles, DN, email).
(LDAP returns a success or fail response and doesn’t return any token)
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Spring Security maps these attributes into authorities/roles.
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If valid → the request is authenticated and authorized.
Spring Example
What this does:
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Uses LDAP server as the user store.
Authenticates user with uid from the people directory.
Looks up user roles in the groups directory.
Connects to an LDAP server running locally.
Advantages
- Centralized authentication (all users managed in LDAP/Active Directory).
- Mature and widely used in corporate environments.
- Easy integration with existing IT infrastructure.
- Works well with large organizations.
Limitations
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Complex setup compared to Basic Auth or JWT.
Requires maintaining an LDAP server.
Not as flexible for modern microservices (JWT/OAuth2 often preferred).
Network dependency → if LDAP server is down, login fails.
No tokens (like JWT) → each login requires LDAP verification.
LDAP is stateful and may become a bottleneck for large-scale public apps.
Best suited for intranet/corporate use, not internet-scale systems.
Real-World Analogy
Think of LDAP like a corporate HR directory:
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Every employee is listed with details (name, ID, role, department).
When you enter a building, security checks your ID card against the directory.
They also check your department/role to decide what areas you can access.
Use Cases
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Corporate networks using Active Directory or OpenLDAP.
Enterprise apps that need centralized employee login and role management.
Internal APIs and systems where users are already managed in LDAP.
👉 LDAP Authentication is best suited for enterprises with centralized user directories, while modern cloud apps often prefer OAuth2/OIDC + JWT for scalability and federation.
👉 In short: LDAP authentication in Spring validates credentials directly against an LDAP/AD server and maps groups/roles into Spring Security for authorization.
5) SAML (Security Assertion Markup Language)
Definition
SAML (Security Assertion Markup Language) is an XML-based protocol used for Single Sign-On (SSO) in enterprise environments.
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It allows Identity Providers (IdP) (e.g., Okta, ADFS, Ping Identity) to authenticate users and pass that authentication information to Service Providers (SP) (your application).
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Common in enterprises where multiple internal systems need to trust a central login.
How It Works (Step by Step)
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A user tries to access a Service Provider (SP), e.g., a corporate app.
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The SP redirects the user to the Identity Provider (IdP).
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The user authenticates at the IdP (username/password, smart card, etc.).
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The IdP creates and sends back a SAML Assertion (an XML document containing user identity + attributes) to the SP.
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The SP validates the assertion’s signature and extracts identity/roles.
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If valid → the SP grants access.
👉 Unlike OAuth2/JWT, SAML assertions are XML-based and often transmitted via browser redirects (POST bindings).
Spring Example (Spring Security SAML2)
Add dependency:
Java Config (Service Provider side):
What this does:
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Configures Spring Boot as a SAML Service Provider.
Redirects login attempts to the IdP.
After successful authentication, maps SAML assertion attributes to Spring Security authorities.
Advantages
- Widely used in enterprises for SSO across legacy and modern apps.
- Mature, standardized protocol supported by most enterprise IdPs.
- Can carry rich identity data (roles, departments, attributes) in assertions.
Limitations
- Verbose XML format → heavier than JWT/OIDC.
- More complex to configure than OAuth2/OIDC.
- Not ideal for mobile or modern REST APIs (OIDC is preferred there).
- Works best in enterprise intranets, less common for public internet apps.
Real-World Analogy
Think of SAML like a passport system in a corporate campus:
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You log in at the security desk (IdP).
Security issues a signed document (SAML assertion).
Each building’s entrance (Service Provider) reads and validates that document → decides if you’re allowed in.
Use Cases
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Enterprise SSO across multiple internal systems (HR, finance, intranet portals).
Organizations with Active Directory Federation Services (ADFS).
Large corporations needing integration between cloud apps (Salesforce, Workday) and on-prem apps.
👉 In short:
-
SAML is an enterprise-grade SSO protocol, best for legacy and corporate environments.
-
For modern microservices and APIs, OAuth2/OIDC with JWT is usually preferred.
6) API Key Authentication
Definition
API Key Authentication is a simple token-based mechanism where the client includes a unique API key in every request (commonly in headers or query parameters).
How It Works (Step by Step)
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A client registers with the API provider and receives a unique API key.
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The client sends this key with each request, e.g.:
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The server checks the validity of the API key.
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If valid → the request is authenticated and authorized.
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If invalid/missing → the server rejects the request with 401 Unauthorized or 403 Forbidden.
👉 API keys do not carry identity or role info (unlike JWT or SAML). They are just shared secrets.
Spring Example
Custom filter approach:
Register the filter in SecurityConfig:
Advantages
- Simple to implement (no complex tokens or identity providers).
- Lightweight – just check a key string.
- Works well for server-to-server communication.
Limitations
- Keys can be stolen if exposed (must always use HTTPS).
- No built-in support for user identity or roles.
- Hard to rotate/manage at scale compared to OAuth2/JWT.
- Not ideal for large distributed systems needing fine-grained authorization.
Real-World Analogy
Think of an API key like a membership card at a club:
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If you show the card (API key), you’re allowed inside.
The card itself doesn’t prove who you are or what access level you should have → it only proves possession of the key.
Use Cases
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Public APIs (Google Maps, Weather APIs, Payment gateways).
Internal services that just need basic authentication.
Microservices communication when simple secret-based access is enough.
Quick prototyping or non-critical APIs.
👉 In short:
API Key Authentication is fast and simple, but less secure and less flexible than OAuth2/JWT. Best for lightweight APIs or internal use cases.
👉 How you can generate an API Key in Spring Boot
In a Spring Boot application, API keys can be generated using Java SecureRandom or UUID, stored in a database, and assigned to clients at registration.
Example (Java):
👉 Store this key in the database and provide it to the client during onboarding.
👉 Each request must include the key in headers:
7) Form-Based Login
Definition
Form-Based Login is a traditional authentication method where users log in with a username and password via an HTML form. The server creates and manages a session (using cookies) to maintain user authentication across multiple requests.
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Stateful approach → the server stores session information.
Commonly used in traditional web applications (Spring MVC, JSP, Thymeleaf, etc.).
How It Works (Step by Step)
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The user navigates to the application and tries to access a protected resource.
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Spring Security redirects the user to the login page (/login).
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The user submits credentials via an HTML login form.
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Spring Security validates the credentials against the configured authentication provider (in-memory, DB, LDAP, etc.).
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If valid → a session is created, and a JSESSIONID cookie is sent to the client.
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For each subsequent request, the browser automatically sends the cookie.
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The server uses the session to authenticate and authorize the user.
Spring Example
What This Does
-
Requires all requests to be authenticated.
Configures a form-based login page at /login.
Allows unauthenticated users to access the login page.
Spring Security automatically handles session creation and management.
Advantages
-
Simple and familiar (used in most web apps).
Built-in support in Spring Security (minimal configuration).
Can be customized with themes, error handling, and redirects.
Works well with server-side rendered apps (Thymeleaf, JSP).
Limitations
-
Not stateless → requires server-side session storage.
Not ideal for microservices (scaling session management is hard).
Vulnerable to CSRF attacks (must enable CSRF protection).
Less suited for APIs or SPAs (JWT/OAuth2 preferred there).
Real-World Analogy
Think of a hotel check-in:
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You provide your ID (username/password) at the front desk (login form).
If valid, the hotel gives you a key card (session cookie).
Each time you want to access your room, you just show the key card (session).
Use Cases
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Traditional Spring MVC applications.
Intranet applications where session management is manageable.
Apps where user experience needs a custom login page.
👉 In short: Form-Based Login in Spring Security is best for traditional web apps with server-side session management, but less suited for stateless APIs and modern microservices.
Comparison Table of Authentication Approaches
Approach | Stateless | Token Type / Session | Use Case |
OAuth 2.0 | Yes | JWT | Centralized microservice auth |
JWT | Yes | JWT | Stateless API auth |
Basic Auth | No | None | Internal APIs, quick prototyping |
LDAP | No | None | Corporate directory auth |
SAML | No | XML Assertion | Enterprise SSO |
API Key | Yes | API key | Public/internal APIs |
Form Login | No | Session | Web apps, traditional login forms |
Authorization Approaches in Spring
Authorization determines what a user is allowed to do. Spring provides several ways to implement it, from roles to fine-grained permissions.
1) Role-Based Access Control (RBAC)
Definition
Role-Based Access Control (RBAC) is an authorization mechanism where access to resources is granted based on a user’s assigned roles (e.g., ADMIN, USER).
-
Each role groups a set of permissions.
Users are mapped to roles, and roles determine what resources they can access.
Widely used in enterprise apps where different users have different levels of access.
How It Works (Step by Step)
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During authentication, the user is assigned one or more roles (from DB, LDAP, or JWT claims).
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Spring Security maps these roles to authorities.
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When a request is made to a protected resource:
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Spring Security checks the user’s roles.
If the required role matches → access is granted.
Otherwise → access is denied (403 Forbidden).
Spring Example
What This Does
-
Restricts /admin/** endpoints to users with the ADMIN role only.
Restricts /user/** endpoints to users with either USER or ADMIN roles.
Requires authentication for all other endpoints.
Advantages
-
Simple and intuitive model (easy to understand & implement).
Well supported in Spring Security (built-in role checks).
Works well for applications with clear role hierarchies (e.g., Admin vs User).
Limitations
-
Not flexible for complex permissions (e.g., per-resource or per-action).
Hard to scale in large enterprises with many roles and fine-grained permissions.
Changes in roles may require code updates or new role definitions.
Real-World Analogy
Think of building access with security badges:
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A User badge lets you access common areas (e.g., cafeteria).
An Admin badge lets you access both common areas and restricted areas (e.g., server room).
Security checks your badge before granting access.
Use Cases
-
Applications with simple role distinctions (e.g., Admin vs Regular User).
Internal portals where employees have roles like HR, Manager, Employee.
APIs where role-based authorization is enough (instead of fine-grained policies).
👉 In short: RBAC is best for applications with clear, hierarchical roles, but for fine-grained or resource-specific access, Attribute-Based Access Control (ABAC) or policy-based approaches (like Spring Security with SpEL or external tools) may be better.
2) Method-Level Security
Definition
Method-Level Security allows you to protect specific methods in controllers or services using annotations, rather than relying only on URL-based authorization.
Key Annotations
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@PreAuthorize – Checks a condition before the method is executed.
@PostAuthorize – Checks a condition after the method has executed.
@Secured – Simple role-based check (alternative to @PreAuthorize).
How It Works (Step by Step)
-
A user makes a request that triggers a controller or service method.
Spring Security evaluates the annotations on the method using the current user’s roles or authorities.
If the condition passes → method executes normally.
If the condition fails → Spring Security returns 403 Forbidden.
Spring Example
What This Does
-
/admin/users → Only users with ADMIN role can access.
/profile → Users with USER or ADMIN roles can access.
Unauthorized users automatically get 403 Forbidden.
Advantages
-
Provides fine-grained security beyond URL-based checks.
Easy to apply directly on services or controller methods.
Can use dynamic conditions with SpEL (e.g., check ownership or custom permissions).
Limitations
Real-World Analogy
Think of a manager approving documents:
-
Only managers with certain clearance (roles/permissions) can approve financial reports.
Even if a manager can access the office (URL), they cannot execute specific actions unless authorized.
Use Cases
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Protecting service methods in microservices.
Applying role-based or permission-based access at the method level.
Scenarios where URL-based security is insufficient (e.g., shared endpoints with different logic for roles).
👉 In short: Method-Level Security in Spring allows direct control over who can execute specific methods, providing flexibility and fine-grained authorization.
3) Permission-Based Authorization (Fine-Grained Control)
Definition
Permission-Based Authorization provides fine-grained access control by using specific permissions or authorities rather than broad roles.
-
Examples of authorities: USER_READ, USER_WRITE, ORDER_APPROVE.
Offers more control than Role-Based Access Control (RBAC), especially in complex applications.
How It Works (Step by Step)
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Assign authorities to roles or directly to individual users.
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Use Spring Security annotations to enforce permissions at the method or endpoint level:
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When a user invokes a method, Spring Security evaluates if the required authority is present.
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If the user has the authority → method executes; otherwise → 403 Forbidden.
Spring Example
What This Does
-
Restricts access to users who have the USER_READ authority.
Allows fine-grained differentiation between reading, writing, updating, or deleting resources.
Advantages
-
Highly flexible → control access at a granular level.
Can combine roles + permissions for hierarchical or multi-layered access.
Works well in enterprise or multi-tenant systems.
Limitations
-
More complex to manage than simple role-based access.
Requires a clear mapping of roles → permissions → users.
Overuse can lead to annotation clutter in code.
Real-World Analogy
Think of a document management system:
-
Role Editor may have permissions: DOC_READ, DOC_WRITE.
Role Viewer may only have DOC_READ.
Even if both roles can access the “Documents” section, actual operations are restricted by permissions.
Use Cases
-
Applications requiring read vs write separation.
Enterprise apps with multi-level access policies.
Systems where roles alone are too broad for security needs.
👉 In short: Permission-Based Authorization in Spring allows fine-grained control over actions and data, giving developers precise control over who can perform which operations.
Quick Comparison Table
Authorization Type | Level | Example Use Case |
Role-Based (RBAC) | Endpoint / URL | Admin vs User access |
Method-Level Security | Method | Protect controller or service methods |
Permission-Based | Method / Endpoint | Fine-grained control (read/write access) |
2️⃣ API Gateway Security
An API Gateway (like Spring Cloud Gateway, Kong, or Istio Ingress) acts as the entry point for all client requests to microservices. It provides centralized security, routing, and request management.
Features & Examples
-
Token Validation
-
Rate Limiting
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Throttling
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Definition: Gradually slows down excessive requests rather than outright blocking them, preventing service overload.
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Example: If a client exceeds 10 requests/sec, throttle them to 2 requests/sec until the rate normalizes.
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IP Whitelisting
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CORS Control (Cross-Origin Resource Sharing)
Summary:
-
Rate Limiting: Block excess requests.
Throttling: Slow down excess requests.
IP Whitelisting: Only allow trusted networks.
Token Validation & CORS: Ensure authorized and safe access.
This setup ensures security, reliability, and stability for microservices behind the gateway.
3️⃣ Service-to-Service Security
Definition: In a microservices architecture, internal services must trust each other and communicate securely. This prevents unauthorized services from accessing sensitive data or functionality.
Key Techniques
-
mTLS (Mutual TLS)
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Definition: Both the client and server authenticate each other using TLS certificates, not just the server.
-
Purpose: Ensures only trusted services can communicate internally.
-
Spring Example (Service A):
-
Explanation:
-
key-store: certificate & private key for Service A
trust-store: certificates of trusted client services
client-auth: need: forces clients to present valid certificates
-
Service Mesh (Istio / Linkerd)
-
Definition: A dedicated infrastructure layer that automates secure service-to-service communication, including mTLS, routing rules, retries, and zero-trust policies.
-
Benefits:
-
Automatically issues certificates for services
Handles encryption & authentication without code changes
Provides traffic policies, observability, and monitoring
-
Example: Istio sidecar proxy handles mTLS automatically between Service A and Service B, ensuring encrypted and authenticated traffic.
Summary:
-
mTLS: Direct, certificate-based trust between services.
Service Mesh: Automates mTLS and adds advanced traffic/security policies.
This ensures internal communication is secure, authenticated, and encrypted, even within a trusted network.
4️⃣ Data Security
Definition: Protect sensitive data at rest, in transit, and during access in a microservices environment.
Key Techniques
-
Transport Security (HTTPS/TLS)
-
Definition: Encrypts data between clients and services to prevent eavesdropping or tampering.
-
Best Practice: Enforce TLS 1.2+ for all communications.
-
Example: Spring Boot HTTPS configuration:
-
Secret Management
-
Definition: Avoid hardcoding passwords, API keys, or tokens. Use a centralized secret store like HashiCorp Vault.
-
Spring Example: Access secrets from Vault:
-
Password Hashing
-
Definition: Store user passwords in hashed form, never in plain text.
-
Example (Spring Security with BCrypt):
Explanation: BCrypt automatically salts passwords, making it much harder for attackers to reverse-engineer them.
Summary:
-
Transport Security: Encrypt network traffic (HTTPS/TLS).
Secret Management: Securely store and fetch credentials (Vault).
Password Hashing: Store passwords safely (BCrypt or similar).
This ensures sensitive data is encrypted in transit, securely stored, and protected against unauthorized access.
5️⃣ Secure Coding Practices
Definition: Writing code in a way that prevents common vulnerabilities and reduces the risk of attacks.
Key Practices
-
Prevent SQL Injection
-
Disable Stack Traces in Production
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CSRF Protection (Cross-Site Request Forgery)
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Content Security Policy (CSP) Headers
Summary:
-
Use parameterized queries to prevent SQL injection.
Hide stack traces in production.
Enable CSRF protection for session-based apps, disable for JWT APIs.
Add CSP headers to reduce XSS risk.
These practices strengthen the application layer, making it harder for attackers to exploit code-level vulnerabilities.
6️⃣ Monitoring & Auditing
Definition: Continuously observe, log, and analyze application activity to detect security issues, performance problems, or suspicious behavior.
Key Techniques
-
Spring Security Audit Logging
-
Definition: Captures important security-related events such as logins, failed authentication attempts, and access to sensitive endpoints.
-
Example: Spring Boot listener for audit events:
-
Explanation: Logs each security event type (e.g., AUTHENTICATION_SUCCESS) and the user involved (principal).
-
Can be extended to send events to centralized logging systems.
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Centralized Logging & Monitoring
-
Logs:
-
ELK/EFK Stack: Elasticsearch (store), Logstash/Fluentd (ingest), Kibana (visualize)
-
Loki + Promtail + Grafana: Lightweight alternative for logs
-
Metrics:
-
Traces:
Summary:
-
Audit Logging: Tracks security events and user activity.
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Centralized Logging: Aggregates logs for analysis and alerting.
-
Metrics & Traces: Monitor performance, detect bottlenecks, and debug service interactions.
Monitoring and auditing are critical for proactive security, compliance, and operational insight in microservices.
7️⃣ Infrastructure & Container Security
Definition: Secure the underlying infrastructure and containerized environments where microservices run. This ensures services remain protected even if the code is secure.
Key Techniques
1. Docker Security
2. Kubernetes Security
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RBAC (Role-Based Access Control): Restrict which users or service accounts can access cluster resources.
-
Network Policies: Control pod-to-pod communication, limiting exposure.
-
Secrets Management: Store credentials in encrypted Kubernetes Secrets rather than hardcoding.
-
Pod Security Best Practices:
-
Run as non-root user
Use read-only filesystem
Limit capabilities
3. Image Scanning
Summary:
-
Docker: Non-root, minimal, trusted images.
Kubernetes: RBAC, Network Policies, Pod Security, Secrets encryption.
Image Scanning: Detect vulnerabilities early.
This layer ensures secure deployment, access control, and hardened containers, complementing application-level security.
8️⃣ Stable Tech Stack for Securing Spring Microservices
Layer | Recommended Tech | Purpose |
Security Core | Spring Boot + Spring Security | Application-level authentication, authorization, and core security features. |
API Gateway | Spring Cloud Gateway | Centralized entry point, request routing, rate limiting, CORS, IP whitelisting. |
Authentication | Keycloak / Okta / Auth0 | OAuth2 / OpenID Connect-based user identity management. |
Secrets | HashiCorp Vault + Spring Cloud Config | Secure storage and dynamic retrieval of credentials and sensitive config. |
Service Mesh | Istio / Linkerd | Automates mTLS, traffic rules, and zero-trust policies for service-to-service communication. |
Monitoring | Prometheus + Grafana + Loki + Jaeger | Metrics, logging, tracing, and observability for microservices. |
Containerization | Docker + Kubernetes | Secure deployment, orchestration, network isolation, and RBAC-based access control. |
Final Security Checklist
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OAuth2 + JWT for user identity: Secure, token-based authentication for APIs.
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Centralized API Gateway: Enforces rate limiting, CORS policies, and IP whitelisting.
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Service-to-service trust: Use mTLS or a service mesh (Istio/Linkerd) for encrypted and authenticated internal communication.
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Secrets Management: Store all credentials and sensitive configuration in Vault.
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Encrypt data: Ensure encryption in transit (HTTPS/TLS) and at rest (database/files).
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Secure coding practices: Prevent SQL injection, hash passwords, enforce CSRF protection for session-based apps, and implement CSP headers.
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Centralized monitoring & audit logging: Use ELK/EFK or Loki + Grafana for logs, Prometheus + Grafana for metrics, and Jaeger/Zipkin for distributed tracing.
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Hardened infrastructure: Non-root Docker images, Kubernetes RBAC, network policies, and image scanning for vulnerabilities.