Web Authentication (PDF) - SA 2024

Web Authentication HTTP Authentication and Security Considerations October 17th, 2024 Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 1/24  Outline 1. Introduction 2. HTTP Basic 3. HTTP Digest 4. HMAC...

Web Authentication HTTP Authentication and Security Considerations October 17th, 2024 Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 1/24  Outline 1. Introduction 2. HTTP Basic 3. HTTP Digest 4. HMAC authentication 5. Token authentication 6. JSON Web Token (JWT) 7. OAuth2 8. Multi-factor authentication 9. Web Authentication (WebAuthn) 10. OpenID Connect Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 2/24  Authentication vs. authorization 1. Introduction Authentication is the process of ascertaining that somebody really is who he claims to be. Authorization refers to rules that determine who is allowed to do what. E.g. Alice may be authorized to create and delete records, while Bob is only authorized to read. 1 @api.login_required() 2 @api.permission_required( 3 permissions.OwnerRolePermission(Account) 4 ) 5 def get(self, args): 6 """ 7 Return account balance 8 """ Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 3/24  Cryptographic primitives Security Goal Cryptographic primitive Hash MAC Digital signature Integrity Authentication ✘ Non-repudiation ✘ ✘ Kind of keys none symmetric keys asymmetric keys Integrity ▪ The message has not been accidentally modified Authentication ▪ The message originates from the sender Non-repudiation ▪ A third party can be confident that the message originates from the sender Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 4/24  HTTP Basic https://tools.ietf.org/html/rfc2617 2. HTTP Basic Simplest authentication The server responds 401 Unauthorized and asks for authentication in headers 1 HTTP/1.1 401 Unauthorized 2 WWW-Authenticate: Basic realm="flask-restful" Client adds header with ‘user:password’ encoded in base64 1 GET / HTTP/1.1 2 Host: example.org 3 Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ== Handled natively by browser ▪ cannot customize dialog box Vulnerable against eavesdropping if not using SSL/TLS ▪ user and password sent unencrypted but encoded Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 5/24  HTTP Digest I https://tools.ietf.org/html/rfc2617 3. HTTP Digest Secure alternative to HTTP Basic ▪ Challenge-response based ▪ More complex ▪ Still handled natively by browsers The server answers 401 Unauthorized and asks for authentication in headers 1 HTTP/1.1 401 Unauthorized 2 WWW-Authenticate: Digest realm="flask-restful", nonce="dcd98b7102dd2f0e8b11d0f600bfb0c093" Client add authorization header 1 GET / HTTP/1.1 2 Host: example.org 3 Authorization: Digest Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 6/24  HTTP Digest II https://tools.ietf.org/html/rfc2617 Simplest case ▪ HA1 = MD5(username:realm:password) ▪ HA2 = MD5(method:digestURI) ▪ response = MD5(HA1:nonce:HA2) Optional security enhancements ▪ quality of protection (qop) ▪ nonce counter incremented by client ▪ Client-generated random nonce A bit outdated ▪ Only prevent replay attacks Cannot prevent security downgrading ▪ Was defined before Keyed-Hash Message Authentication Code (HMAC) Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 7/24  HMAC Authentication I Keyed-Hash Message Authentication Code 4. HMAC auth. Custom Authorization header content ▪ digest = b64encode(hmac(“sha256”, “secret”, “GET+/users/johndoe/financialrecords”)) GET /users/johndoe/financialrecords HTTP/1.1 Host: example.org Authorization: hmac johndoe: Developer can choose hashing algorithm and what data they want to include ▪ Ensure data integrity ▪ Including the body prevent data tampering Optional in HTTP digest Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 8/24 HMAC Authentication II Keyed-Hash Message Authentication Code source: https://commons.wikimedia.org/wiki/File:SHAhmac.svg Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 9/24  Token authentication 5. Token auth. A token represents the fact that a user is authenticated ▪ Client authenticates using secret/password and ask for a token ▪ Client sends a token in subsequent requests ▪ Can be short or long lived Renew a token using a refresh token Can revoke a token Authenticate with a token ▪ Request parameter GET /api/profile?access_token=LHnDqNVlXg HTTP/1.1 ▪ Authorization header Authorization: Bearer LHnDqNVlXg Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 10/24  JSON Web Token (JWT) https://tools.ietf.org/html/rfc7519 6. JWT. JWTs represent a set of claims as a JSON object that is encoded in a JWS and/or JWE structure. a claim: {“userId”: “pasquier”, “role”: “superuser”} Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 11/24  JSON Web Signature (JWS) https://tools.ietf.org/html/rfc7515 JSON Web Signature (JWS) represents content secured with digital signatures or Message Authentication Codes (MACs) using JSON-based data structures. A JWS consists of: ▪ a JOSE header ▪ a payload ▪ a signature {header}.{payload}.{signature} encoded in base64url Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 12/24  base64url encoding https://tools.ietf.org/html/rfc4648 base64url is a base64 variant 62 alphanumeric characters - instead of + _ instead of / Padding (“=”) is optional URL safe ▪ “.” is unreserved, can be used as separator Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 13/24 Value Char Value Char Value Char Value Char 0 A 16 Q 32 g 48 w 1 B 17 R 33 h 49 x 2 C 18 S 34 i 50 y 3 D 19 T 35 j 51 z 4 E 20 U 36 k 52 0 5 F 21 V 37 l 53 1 6 G 22 W 38 m 54 2 7 H 23 X 39 n 55 3 8 I 24 Y 40 o 56 4 9 J 25 Z 41 p 57 5 10 K 26 a 42 q 58 6 11 L 27 b 43 r 59 7 12 M 28 c 44 s 60 8 13 N 29 d 45 t 61 9 14 O 30 e 46 u 62 - 15 P 31 f 47 v 63 _ Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 14/24  JWE, JWK JSON Web Encryption (JWE) is like JWS but for encrypting data ▪ Enables end-to-end encryption Does not mean we don’t need SSL/TLS anymore!!! JSON Web Key (JWK) is a JSON representation of a cryptographic web key JWT JWK JWS JWE JSON Goto https://jwt.io/ to play and to have a lot of explanation. Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 15/24  OAuth2 I https://tools.ietf.org/html/rfc6749 7. Oauth2 Open standard for authorization ▪ Secure delegated access Enable resource access on behalf of a resource owner from a third-party service Roles ▪ Resource owner ▪ Resource server ▪ Client ▪ Authorization server 4 types of authorization ▪ Authorization Code Grant (server application) ▪ Implicit Grant (client application/browser) ▪ Resource Owner Password Credentials Grant ▪ Client Credentials Grant Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 16/24  OAuth2 II - Client Credentials Grant https://tools.ietf.org/html/rfc6749 Client is ressource owner ▪ No authorization required for end-user ▪ No delegation Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 17/24  OAuth2 II - Client Credentials Grant Without a JWT Without a JWT token the Resource Server has to query informations about the token (scopes, validity,...) Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 18/24  OAuth2 II - Client Credentials Grant With JWT (to use for the project) Provides JWT token in authorization header Authorization: Bearer Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 19/24  OAuth2 III - Implicit Grant https://tools.ietf.org/html/rfc6749 Client application (typ. JavaScript) ▪ e.g. access a Facebook profile from external website No refresh token Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 20/24 Multi-factor authentication 8. Multi-factor auth Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 21/24  Web Authentication (WebAuthn) 9. WebAuthn Browser API for authentication with public key ▪ Useful to authenticate with physical electronic authorization devices (USB tokens, smart-cards...) Enable multi-factor authentication with a possession factor ▪ Single-factor authentication is also possible Universal 2nd Factor (U2F) is a standard interface to USB and NFC tokens. Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 22/24  OpenID Connect 9- OpenID Connect Open standard for authentication ▪ On top of OAuth 2.0 REST principles ▪ Useful for Single Sign-On Client can ▪ Verify the identity of an End-User ▪ Obtain basic profile information about End User Single-sign-on is about logging on in one place and having that authenticate you at other locations automatically. OpenID is about delegating authentication to an OpenID provider so you can effectively log on to multiple sites with the one set of credentials. Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 23/24  Advanced Software Engineering SA 2024 – Prof. Jacques Pasquier - Dr- Mourad Khayati - Quentin Nater 24/24