1. Hasini Gunasinghe
Software Engineer-WSO2

2.  Security requirements of a SOA solution in
healthcare domain.
 Security patterns to accomplish them.
 Implementing patterns with WSO2 ESB.

3. Hospital Services Channelling consultation
Physicians’
Patients’ data data
Ceycare
Systems
Medical Laboratory Collaboration with medical
Services research institutes
Medical Test
results
Medical
statistics

4.  Why SOA?
 Expose legacy sytem components as services.
 Loose coupling
 Interoperability
 Flexibility
 Business process composition.

5.  Why security in SOA?
 Business assets exposed to outside as services to
be discovered.
 Should facilitates interoperability, flexibility.

6.  Identification and authentication
 Authorization
 Intergrity
 Privacy
 Security auditing
 Survivability
 Non-repudiation
Source: Security in SOA-Based Healthcare System

7. Requirement:
Services need to identify and verify the claimed
identity of internal users of the organization.

8. Pattern:
Authentication Patterns:
 Direct Authentication
- Authenticating users with credentials stored internally.
- Credentials can be :
- Username/password
- Username token
- X.509 certificates

9. Patient’s Records:
Name:
Credential 3 Age:
Histroy:
1
Secured Proxy
2
Ceycare
credential
store

10. Requirement:
Services need to identify and verify the claimed
identity of external users – from partner
organizations.

11. Pattern:
Authentication Patterns:
 Brokered Authentication
 Authenticating users outside the organization boundary.
 Ceycare trusts a token issued by a trusted party in partner
organization.
 Brokered authentication based on WS-Trust with SAML.

12. Scenario 1: Authentication accross organizational boundries
CeyCare 4 Patient’s
Records:
Secure Token Name:
Service of Age:
CeyMed Histroy:
2 Secured Proxy
3
CeyMed 1
credential
store
CeyMed

13. Requirement:
Facilitate communication between clients and
services which talk in different authentication
mechanisms.

14. Pattern:
Resource Access Patterns:
 Protocol Transition
 ESB authenticates clients with the auth mechanism
that they understand – eg: UT
 Transform credentials in the form that service
understands - eg: Basic Auth

15. Patient’s
Records:
Name:
Age:
Histroy:
BasicAuth
Header
3
1
2
Username
Token
Ceycare
credential
store

16. Requirements:
- Avoid user credentials to be passed to
backend service.
- Avoid user bypassing security processing.

17. Pattern:
Resource Access Patterns:
 Trusted sub system pattern
 User authenticates to ESB with his/her credentials.
 BE service trusts ESB.
 ESB accesses BE service on behalf of authenticated user.

18. Patient’s
Records:
Name:
ESB Age:
Credential Histroy:
3
User
Credential
Secured Proxy
1
2
Ceycare
credential
store

19. Requirement:
Control access based on privileges of the users.
Eg:
Users in role: ‘Physician’ can update patients’ records
while users in role: ‘Lab technologist’ can only view
records

20. Pattern:
Authorization patterns
 Role based access control:
 Assign users to roles.
 Grant privileges to roles.
 This is a coarse grained authorization model.

21. Requirement:
Control access based on user’s claims, in a fine
grained manner.
Eg:
Heart patients data could only be accessed by
Physicians with job title: “Cardiologists”

22. Pattern:
Authorization patterns
 Claim based authorization :
 Provides fine grained authorization.
 Policy based access control with XACML –
provides flexibilty.

23. Authorization based on claims carried in SAML token.
Heart
Patient’s
Records:
(4) Allow/deny Name:
access Age:
Histroy:
SAML
Token Secured Proxy
1 (3) Authorization
decision
Entitlement PAP, PDP,
Mediator (2) XACML PIP
[PEP] Authorization
request

24. Requirement:
Delegating access:
Eg:
Application in a phisician’s mobile device needs to
retrieve channelling appointments from his account
in Ceycare System.

25. Pattern:
Authorization patterns
 Constrained delegation using OAuth:
1. Mobile app authenticates to authorization server.
2. Mobile app requests authorization from resource owner.
3. Resource owner authenticates to authorization server.
4. Resource owner grants permissions to the application to
access resource on behalf of him.
5. Application obtains access token from access grant.
6. Resource server (ESB) validates access token.
7. Allow/Deny access to BE resource.

26. Chanelling
appointments
Name:
Time:
(7) Allow/ Hospital:
Access request+ deny
Access Token OAuth access
5 Mediator
(6) Validate Access Token
Authorization
1
request
(4) Access Token
2
Authorization (3) Authorization grant
grant

27. Requirements:
 Protect sensitive personal data during
transmission from :
 tampering
 unauthorized access
 Non-repudiation - A patient’s account should
show who has updated his/her medical
records.

28. Patterns:
Message protection patterns:
 Data origin authentication and intergrity -
digital signatures.
 Data confidentiality - digital encyption.

29. Example Configuration:

30. Example Configuration:

31. Requirement:
Avoid exposing sensitive data through exceptions.
 Legacy application code might throw exceptions
containing sensitive information.
 Need to filter those expections when system is exposed
to external parties.

32. Pattern:
Boundry defense pattern
 Exception shielding:
- Sanitize unsafe exception data by replacing it with
non-harmful exception message.
- Enrich mediator of ESB.

33.  Example un-safe message:

34.  Example Configuration:

35. Requirement:
Log security incidents to trace system abuse:
- Failed login attempts
- Unauthorized access attempts to services

36. Pattern:
Boundry defense pattern:
 Audit Intercepter
 All messages flow through the a gateway of the
system. (ESB)
 Necessary auditing is done by the logging at the
gateway. (Log mediators of ESB)

37. Example Configuration:

38. Requirement:
Prevent denial of service attacks caused by
replaying valid messages.

39. Pattern:
Boundray defense pattern
 Replay mitigation:
- Apply throttling rules at the entry point
(ESB).
- Validate message freshness by WS-Security
mechanisms (Timestamp).

40. Applying throttling rules in ESB:
Control access at three different levels through
throttling:
1. Global
2. Service
3. Operation

41.  Throttling at global level:

42.  Throttling at service level:

43.  Configuring throttling in ESB:

44.  Example Time Stamp in WS-Security Header:

45. Requriement:
Mitigate damages to the system from messages
with malicious content :
- SQL injection
- X-Doc attacks

46. Pattern:
Boundray defense pattern
 Message validation :
- XML Schema validation.
- Regular expression validation to avoid SQL
injections contained in strings.
- Validation & Filter mediators of ESB.

47.  Examlpe SQL Injection attack:
Query:
SELECT * FROM p r e s c r i p t i o n s WHERE pat i ent ID = ' + $pat i ent ID +' ;
If
$pat i ent ID = 3 5 2 1 ' ; DROP TABLE p a t i e n t s ;
Resulting query causing SQL injection:
SELECT FROM p r e s c r i p t i o n s WHERE pat i ent ID = ' 3 5 2 1 ' ;
DROP TABLE p a t i e n t s ;
Source: Security in SOA-Based Healthcare System

48.  Example Configuration:

49.  Security requierments related to a healthcare
SOA solution.
 Security patterns used to accomplish them.
 How WSO2 ESB fits in the security patterns.

50.  WSO2 Security & Identity Gateway solution
white paper:
http://wso2.com/casestudies/wso2-security-and-
identity-gateway-solution/
 Security in SOA based healthcare systems:
By Richard Sassoon

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