1. Multi-party Authentication in Web Services
Madhumita Chatterjee
Dt :28th October 2004
12/8/2018 5:03 PM

2. Overview Web Services Architecture Typical Scenario Security Threats
Challenges and issues
Need for Session Authentication
Maruyama’s Protocol
A Proposal
12/8/2018 5:03 PM

3. Web Service Components
Internet based modular applications
Program to program communication
XML
WSDL
SOAP
UDDI
12/8/2018 5:03 PM

4. Web Service Architecture
Implementation of Services
(components)
UDDI
Interface Description with WSDL
1. Request
4. Request
Service requester
Service Broker
Web
Server
For SOAP S E R V I C e
12/8/2018 5:03 PM

5. Web Service Workflows Dynamic composition Multiple instances
Workflow involves service instances belonging to different Web services
Multiple parties belong to a flow.
12/8/2018 5:03 PM

6. Typical Web Service Scenario
Buyer
Govt service
Financer
Provider
Shipper
B.1
G.1
P.2
S.1
P.1
F.2
Service
Instance
Insurance
I.1
F.1
12/8/2018 5:03 PM

7. Web Service Security
Authentication: Establishing identity of user by providing a set of credentials. In return user receives a security token that can be used to access the server.
Authorization: Establishing what a user is allowed to do.
12/8/2018 5:03 PM

8. Web Service Security……cont
Confidentiality: Ensuring that only the intended recipient can read the message, accompanied by encryption.
Integrity: Ensuring that the message has not been tampered with, generally accomplished with digital signatures.
12/8/2018 5:03 PM

9. Threats…. Unauthorized access Parameter manipulation
Network eavesdropping
Message replay
12/8/2018 5:03 PM

10. Challenges Dealing with un-trusted clients.
Application internals are exposed.
SOAP messages are not point to point
Challenge is to preserve security of SOAP message from initial SOAP sender to ultimate SOAP receiver.
12/8/2018 5:03 PM

11. SSL is inadequate SSL provides point-to-point security
Web Services need end-to-end security
SSL does not support
End-to-end confidentiality
Element wise signing and encryption
Non-repudiation
12/8/2018 5:03 PM

12. Need for session Authentication
TA-1
TA-2
Hotel
Flight
Car#1
Car#2
12/8/2018 5:03 PM

13. Maruyama’s protocol
Session Authenticator component responsible for distributing keys and authenticating messages
Each instance belonging to a session gets the shared key
12/8/2018 5:03 PM

14. Maruyama’s protocol….cont
Message authentication protocol
transports authentication information between session participants
Session management protocol
responsible for starting, running and ending a particular session.
12/8/2018 5:03 PM

15. Message Authentication
Session Authenticator
Allows service instances to mutually verify transient membership
Service Authenticator
Protocol for sending Web service to send MACed SOAP envelope to receiving Web Service
12/8/2018 5:03 PM

16. Session Authenticator
Sending instance prepares SOAP envelope
Optionally uses XML encryption
Adds authentication to SOAP header
Using SOAP-DSIG applies MAC to envelope under session key.
12/8/2018 5:03 PM

17. Session Auth….cont… Receiver checks for session key.
Else obtains key from session manager.
Validates MAC and accepts SOAP envelope.
Decrypts encrypted message.
Receiver now has authenticated mesg and session handle.
12/8/2018 5:03 PM

18. Service Authenticator
Sending service prepares SOAP envelope.
Adds authentication header.
Uses SOAP-DSIG to digitally sign mesg.
Optionally uses XML encryption.
Receiver decrypts, validates signature, verifies its own sign and accepts.
12/8/2018 5:03 PM

19. Session Management Initiator of session could be SA
Assigning session Ids.
Creating session secrets.
Maintaining status information for each session.
Keeping participants informed of the status.
Shutting down sessions.
12/8/2018 5:03 PM

20. Online session Management
12/8/2018 5:03 PM

21. Drawbacks .. SA cannot measure the validity of service instance
Anyone who has session ID can contact SA.
An attacker who has compromised an instance can request to join session
No unique identifier for each instance
12/8/2018 5:03 PM

22. Issues not considered What if Session Manager is malicious??
12/8/2018 5:03 PM

23. A Proposal….Adaptive approach
Requirements of users may vary.
Is there need for stringent measures uniformly to every node and transaction
Can we apply as much security as a particular transaction requires?
12/8/2018 5:03 PM

24. Sophisticated Web Services
E.g order for aircraft engine
Spawns multiple supporting transactions
Orders to individual parts
Orders for shipping containers
Etc
Involves handling huge volumes of traffic
12/8/2018 5:03 PM

25. Adaptive approach ….cont
For Simple Web services existing security measures may suffice.
For sophisticated Web Services involving long transactions trusted third party model desirable.
Can an adaptive/hybrid approach be implemented???
12/8/2018 5:03 PM

26. References
1. S. Hada and H. Maruyama, “Session Authentication Protocol for Web Services,”
Proc IEEE Symposium on Application and the Internet, pp , Jan
2. Dacheng Zhang and Jie Xu, “Multi-Party Authentication for Web Services:
Protocols, Implementation and Evaluation,” Proc IEEE Symposium on
Object Oriented Real-time Distributed Computing.
3. M.Hondo, N. Nagaratnam, A.Nadalin, “Securing Web Services,” IBM Systems Journal,
Vol 41, No. 2, 2002.
4. David Geer, “Taking Steps to Secure Web Services,” IEEE Computer, Vol 36,
Oct 2003.
5. V Vasudevan, “A Web Services Primer”,
April 2001.
6. Y. Nakamur, S. Hada and R. Neyama, “Towards the Integration of
Web Services Security on Enterprise Environments,” Proc Symposium on
Applications and the Internet, pp , Jan
7. W3C NOTE, Simple Object Access Protocol (SOAP) 1.1,
12/8/2018 5:03 PM

27. References 8. W3C NOTE, SOAP Security Extensions: Digital Signature,
9. Web `Services Security(WS-Security),
10. Web Services Security Threats and Countermeasures,
Microsoft Corporation, Jan 2004.
12/8/2018 5:03 PM