The document discusses different approaches to method level security in Spring Security including @PreAuthorize, @PostAuthorize, @PreFilter, and @PostFilter annotations. @PreAuthorize allows restricting access to methods based on roles or expressions while @PostAuthorize controls access based on method return values. @PreFilter and @PostFilter can filter collections passed as method parameters or returned.

1. Soham Sengupta
https://github.com/trainerpb 1

2. Basic Approaches of Spring Security
1. URL level security (We already know this)
2. Method level security
3. Entity /Object Level security
https://github.com/trainerpb 2

3. Method Level Security- what & why?
 Additional Layer of Security
 Decouple & less-rely on Front-end logic for ‘ROLE based access ‘
 Survives in case of developer- mistake (E.g. renaming paths – which
allowed other roles to access resources)
https://github.com/trainerpb 3

4. What does that mean?
https://github.com/trainerpb 4

5. Let’s prevent the method ,too
https://github.com/trainerpb 5

6. What happens?
 Even if any other role is allowed to access /doA
 Access to this method will be FORBIDDEN (HTTP Status: 403)
 @PreAuthorize is capable of:
 Evaluating Spring Expressions
 Access Method Parameters
https://github.com/trainerpb 6

7. @PostAuthroize
 This helps control access to succeed depending on returned value of the
method
 E.g. -a very silly impractical USE-CASE-
 Let Access succeed as long length of the username <= Radom() mod 8
https://github.com/trainerpb 7

8. @PreFilter
 Helps filter out from a method, objects from a Collection passed as
parameter to a method
https://github.com/trainerpb 8

9. @PreFilter – Contd.
 Use Case – List all Users except yourself – (E.g. Facebook –chat pane
shows all friends of your but not you!)
https://github.com/trainerpb 9

10. @PreFilter – Contd.
Assignment – What happens if more than one
Collection are passed in parameter list?
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11. @PostFilter
 This helps filter returned Collection based on some criteria that is returned
https://github.com/trainerpb 11

12. Other Approaches- @Secured
https://github.com/trainerpb 12
@Secured annotation doesn’t support Spring Expression Language
What’ll be the @PreAuthorize equivalent of the above code snippet?

13. Another Approach- @RoleAllowed
https://github.com/trainerpb 13
What’ll be the @PreAuthorize equivalent of the above code snippet?

14. Combining @’s together
 We can put multiple annotations together on a method.
 I want a method
 To be available to ADMIN only
 Then, I want to return Collection of records of logged-in user only
https://github.com/trainerpb 14

15. Important Notes-
1. By default, Spring AOP proxy-ing is used to apply method security
 Security will be ignored fora secure method m1() called by another method
m2() in the same class
2. Thread-bound Security Context-
 security context isn’t propagated to child-threads
3. We can use @PreAuthroize or similar annotations at class-level to
ensure ROLE_BASED access to that class.
https://github.com/trainerpb 15

16. https://github.com/trainerpb 16