The learning curve for security is severe and unforgiving. Specifications promise infinite flexibility, habitually give old concepts new names, are riddled with extensions, and almost seem designed to deliberately confuse. For a back-end REST developer, choking all this down for the first time is mission impossible. With an aggressive distaste for fancy terminology, this session delves into OAuth 2.0 as it pertains to REST and shows how it falls into two camps: stateful and stateless. The presentation also details a competing Amazon-style approach called HTTP Signatures and digs into the architectural differences of all three, with a heavy focus on the wire, showing actual HTTP messages and enough detail to have you thinking, “I could write this myself.”

1. JavaOne
#RESTSecurity @dblevins @tomitribe
Deconstructing REST Security
David Blevins
Tomitribe

2. JavaOne
#RESTSecurity @dblevins @tomitribe
“The nice thing about standards is
you have so many to choose from.”
- Andrew S. Tanenbaum

3. JavaOne
#RESTSecurity @dblevins @tomitribe
Focus Areas
• Beyond Basic Auth
• Theory of OAuth 2.0
• Introduction of JWT
• Google/Facebook style API security
• Stateless vs Stateful Architecture
• HTTP Signatures
• Amazon EC2 style API security

4. JavaOne
#RESTSecurity @dblevins @tomitribe
Baseline Architecture
1000 users
x 3 TPS
4 hops
3000 TPS
frontend
12000 TPS
backend

5. JavaOne
#RESTSecurity @dblevins @tomitribe
Basic Auth
(and its problems)

6. JavaOne
#RESTSecurity @dblevins @tomitribe
Basic Auth Message
POST /painter/color/object HTTP/1.1
Host: localhost:8443
Authorization: Basic c25vb3B5OnBhc3M=
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/json
Content-Length: 45
{"color":{"b":255,"g":0,"name":"blue","r":0}}

7. JavaOne
#RESTSecurity @dblevins @tomitribe
Basic Auth
Password Sent
3000 TPS
(HTTP+SSL)
username+password
Base64
(no auth)
3000 TPS
(LDAP)
12000 TPS
(HTTP)

8. JavaOne
#RESTSecurity @dblevins @tomitribe
Basic Auth
Password Sent
3000 TPS
(HTTP+SSL)
username+password
Base64
username+password
Base64
15000 TPS
(LDAP)
Password Sent
12000 TPS
(HTTP)

9. JavaOne
#RESTSecurity @dblevins @tomitribe
Basic Auth
Password Sent
3000 TPS
(HTTP+SSL)
username+password
Base64
IP
whitelisting
3000 TPS
(LDAP)
12000 TPS
(HTTP)

10. JavaOne
#RESTSecurity @dblevins @tomitribe
“Hey, give me all
of Joe’s salary
information.”
“I don’t know
who you are,
…
but sure!”

11. JavaOne
#RESTSecurity @dblevins @tomitribe
Latveria Attacks

12. JavaOne
#RESTSecurity @dblevins @tomitribe
Basic Auth - Attacks
Valid
Password Sent
3000 TPS
(HTTP+SSL) IP
whitelisting
9000 TPS
(LDAP)
12000 TPS
(HTTP)
Invalid
Password Sent
6000 TPS
(HTTP+SSL)

13. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0
(and its problems)

14. JavaOne
#RESTSecurity @dblevins @tomitribe

15. JavaOne
#RESTSecurity @dblevins @tomitribe

16. JavaOne
#RESTSecurity @dblevins @tomitribe

17. JavaOne
#RESTSecurity @dblevins @tomitribe

18. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2 - Password Grant
(LDAP)
(Token Store)
POST /oauth2/token
Host: api.superbiz.io
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/x-www-form-urlencoded
Content-Length: 54
grant_type=password&username=snoopy&password=woodstock
HTTP/1.1 200 OK
Content-Type: application/json;charset=UTF-8
Cache-Control: no-store
Pragma: no-cache
{
"access_token":"2YotnFZFEjr1zCsicMWpAA",
"expires_in":3600,
"refresh_token":"tGzv3JOkF0XG5Qx2TlKWIA",
}
Verify
Password
Generate
Token

19. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0 Message
POST /painter/color/object HTTP/1.1
Host: api.superbiz.io
Authorization: Bearer 2YotnFZFEjr1zCsicMWpAA
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/json
Content-Length: 45
{"color":{"b":255,"g":0,"r":0,"name":"blue"}}

20. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0 Message
POST /painter/color/palette HTTP/1.1
Host: api.superbiz.io
Authorization: Bearer 2YotnFZFEjr1zCsicMWpAA
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/json
Content-Length: 46
{"color":{"b":0,"g":255,"r":0,"name":"green"}}

21. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0 Message
POST /painter/color/select HTTP/1.1
Host: api.superbiz.io
Authorization: Bearer 2YotnFZFEjr1zCsicMWpAA
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/json
Content-Length: 44
{"color":{"b":255,"g":0,"r":0,"name":"red"}}

22. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0 Message
POST /painter/color/fill HTTP/1.1
Host: api.superbiz.io
Authorization: Bearer 2YotnFZFEjr1zCsicMWpAA
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/json
Content-Length: 49
{"color":{"b":255,"g":255,"r":0,"name":"yellow"}}

23. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0 Message
POST /painter/color/stroke HTTP/1.1
Host: api.superbiz.io
Authorization: Bearer 2YotnFZFEjr1zCsicMWpAA
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/json
Content-Length: 49
{"color":{"b":255,"g":200,"r":0,"name":"orange"}}

24. JavaOne
#RESTSecurity @dblevins @tomitribe
401

25. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2 - Refresh Grant
(LDAP)
(Token Store)
Verify
Password
Generate
Token
POST /oauth2/token
Host: api.superbiz.io
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/x-www-form-urlencoded
Content-Length: 54
grant_type=refresh_token&refresh_token=tGzv3JOkF0XG5Qx2TlKWIA
HTTP/1.1 200 OK
Content-Type: application/json;charset=UTF-8
Cache-Control: no-store
Pragma: no-cache
{
"access_token":"6Fe4jd7TmdE5yW2q0y6W2w",
"expires_in":3600,
"refresh_token":"hyT5rw1QNh5Ttg2hdtR54e",
}

26. JavaOne
#RESTSecurity @dblevins @tomitribe
Old pair
• Access Token 2YotnFZFEjr1zCsicMWpAA
• Refresh Token tGzv3JOkF0XG5Qx2TlKWIA
New pair
• Access Token 6Fe4jd7TmdE5yW2q0y6W2w
• Refresh Token hyT5rw1QNh5Ttg2hdtR54e

27. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0 Message
POST /painter/color/palette HTTP/1.1
Host: api.superbiz.io
Authorization: Bearer 6Fe4jd7TmdE5yW2q0y6W2w
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/json
Content-Length: 46
{"color":{"b":0,"g":255,"r":0,"name":"green"}}

28. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0 Message
POST /painter/color/select HTTP/1.1
Host: api.superbiz.io
Authorization: Bearer 6Fe4jd7TmdE5yW2q0y6W2w
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/json
Content-Length: 44
{"color":{"b":255,"g":0,"r":0,"name":"red"}}

29. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0 Message
POST /painter/color/fill HTTP/1.1
Host: api.superbiz.io
Authorization: Bearer 6Fe4jd7TmdE5yW2q0y6W2w
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/json
Content-Length: 49
{"color":{"b":255,"g":255,"r":0,"name":"yellow"}}

30. JavaOne
#RESTSecurity @dblevins @tomitribe
What have we achieved?

31. JavaOne
#RESTSecurity @dblevins @tomitribe
You have more passwords
(at least your devices do)

32. JavaOne
#RESTSecurity @dblevins @tomitribe
Term Alert
• Password Grant???
• Logging in
• Token?
• Slightly less crappy password
• Equally crappy HTTP Session ID

33. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2
Tokens Sent
3000 TPS
(HTTP+SSL)
IP
whitelisting
3000 TPS
(token checks)
Password Sent
1000/daily
(HTTP+SSL)
OAuth 2
(LDAP)
4 hops
12000 TPS
backend

34. JavaOne
#RESTSecurity @dblevins @tomitribe

35. JavaOne
#RESTSecurity @dblevins @tomitribe
“Who the heck
is
6Fe4jd7TmdE5y
W2q0y6W2w
???????”
“No idea, dude.
Ask the token
server.”

36. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2
Tokens Sent
3000 TPS
(HTTP+SSL)
IP
whitelisting
3000 TPS
(token checks)
Password Sent
1000/daily
(HTTP+SSL)
OAuth 2
(LDAP)
12000 TPS
(token checks)
8 hops
24000 TPS
backend

37. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2
Tokens Sent
3000 TPS
(HTTP+SSL)
IP
whitelisting
3000 TPS
(token checks)
Password Sent
1000/daily
(HTTP+SSL)
OAuth 2
(LDAP)
12000 TPS
(token checks)
8 hops
24000 TPS
backend
55% of all traffic

38. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2
Tokens Sent
3000 TPS
(HTTP+SSL)
IP
whitelisting
0 TPS
(token checks)
Password Sent
1000/daily
(HTTP+SSL)
OAuth 2
(LDAP)
0 TPS
(token checks)
0 hops
0 TPS
backend

39. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2
Pointer Pointer
State

40. JavaOne
#RESTSecurity @dblevins @tomitribe
Access Token
Access Pointer?
Access Primary Key?

41. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0
High Frequency Password
Exchange Algorithm?

42. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0
+
JSon Web Tokens (JWT)

43. JavaOne
#RESTSecurity @dblevins @tomitribe
JSon Web Token
• Pronounced “JOT”
• Fancy JSON map
• Base64 URL Encoded
• Digitally Signed (RSA-SHA256, HMAC-SHA512, etc)
• Built-in expiration

44. JavaOne
#RESTSecurity @dblevins @tomitribe
Access Token Previously
• 6Fe4jd7TmdE5yW2q0y6W2w

45. JavaOne
#RESTSecurity @dblevins @tomitribe
Access Token Now
• eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJ0b2tlbi10eXBlIjoi
YWNjZXNzLXRva2VuIiwidXNlcm5hbWUiOiJzbm9vcHkiLCJhb
mltYWwiOiJiZWFnbGUiLCJpc3MiOiJodHRwczovL2RlbW8uc3
VwZXJiaXouY29tL29hdXRoMi90b2tlbiIsInNjb3BlcyI6WyJ0d2l
0dGVyIiwibWFucy1iZXN0LWZyaWVuZCJdLCJleHAiOjE0NzQy
ODA5NjMsImlhdCI6MTQ3NDI3OTE2MywianRpIjoiNjY4ODFi
MDY4YjI0OWFkOSJ9.DTfSdMzIIsC0j8z3icRdYO1GaMGl6j1I_2
DBjiiHW9vmDz8OAw8Jh8DpO32fv0vICc0hb4F0QCD3KQnv8
GVM73kSYaOEUwlW0k1TaElxc43_Ocxm1F5IUNZvzlLJ_ksFXG
DL_cuadhVDaiqmhct098ocefuv08TdzRxqYoEqYNo

46. JavaOne
#RESTSecurity @dblevins @tomitribe
Access Token Now
• header (JSON > Base64 URL Encoded)
• describes how the token signature can be checked
• payload (JSON > Base64 URL Encoded)
• Basically a map of whatever you want to put in it
• Some standard keys such as expiration
• signature (Binary > Base64 URL Encoded
• The actual digital signature
• made exclusively by the /oauth2/token endpoint
• If RSA, can be checked by anyone

47. JavaOne
#RESTSecurity @dblevins @tomitribe
• { "alg": “RS256", "typ": “JWT" }
• {
"token-type": "access-token",
"username": "snoopy",
"animal": "beagle",
"iss": "https://demo.superbiz.com/oauth2/token",
"scopes": [
“twitter”, "mans-best-friend"
],
"exp": 1474280963,
"iat": 1474279163,
"jti": "66881b068b249ad9"
}
• DTfSdMzIIsC0j8z3icRdYO1GaMGl6j1I_2DBjiiHW9vmDz8OAw8Jh8DpO32fv0vIC
c0hb4F0QCD3KQnv8GVM73kSYaOEUwlW0k1TaElxc43_Ocxm1F5IUNZvzlLJ_ks
FXGDL_cuadhVDaiqmhct098ocefuv08TdzRxqYoEqYNo

48. JavaOne
#RESTSecurity @dblevins @tomitribe
Subtle But High Impact
Architectural Change

49. JavaOne
#RESTSecurity @dblevins @tomitribe
What we had
(quick recap)

50. JavaOne
#RESTSecurity @dblevins @tomitribe
(LDAP)
Pull User Info
From IDP

51. JavaOne
#RESTSecurity @dblevins @tomitribe
(LDAP)
Generate an
Access Token
(pointer)

52. JavaOne
#RESTSecurity @dblevins @tomitribe
(LDAP)
Insert both
into DB

53. JavaOne
#RESTSecurity @dblevins @tomitribe
(LDAP)
Send Access Token (pointer)
to client

54. JavaOne
#RESTSecurity @dblevins @tomitribe
Results
Client Holds Pointer Server Holds State

55. JavaOne
#RESTSecurity @dblevins @tomitribe
What we can do now
(Hello JWT!)

56. JavaOne
#RESTSecurity @dblevins @tomitribe
(LDAP)
Pull User Info
From IDP

57. JavaOne
#RESTSecurity @dblevins @tomitribe
(LDAP)
Format the data
as JSON

58. JavaOne
#RESTSecurity @dblevins @tomitribe
(LDAP)
RSA-SHA 256
sign JSON

59. JavaOne
#RESTSecurity @dblevins @tomitribe
(LDAP)
Insert only
pointer
into DB
(for revocation)

60. JavaOne
#RESTSecurity @dblevins @tomitribe
(LDAP)
Send Access Token (state)
to client

61. JavaOne
#RESTSecurity @dblevins @tomitribe
Client Holds State Server Holds Pointer
Desired
Results

62. JavaOne
#RESTSecurity @dblevins @tomitribe

63. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2 - Password Grant
(LDAP)
(Token ID Store)
POST /oauth2/token
Host: api.superbiz.io
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/x-www-form-urlencoded
Content-Length: 54
grant_type=password&username=snoopy&password=woodstock
Verify
Password
Generate
Signed
Token
HTTP/1.1 200 OK
Content-Type: application/json;charset=UTF-8
Cache-Control: no-store
Pragma: no-cache
{
"access_token":"eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.
eyJ0b2tlbi10eXBlIjoiYWNjZXNzLXRva2VuIiwidXNlcm5hb
WUiOiJzbm9vcHkiLCJhbmltYWwiOiJiZWFnbGUiLCJpc3M
iOiJodHRwczovL2RlbW8uc3VwZXJiaXouY29tL29hdXRoM
i90b2tlbiIsInNjb3BlcyI6WyJ0d2l0dGVyIiwibWFucy1iZXN0
LWZyaWVuZCJdLCJleHAiOjE0NzQyODA5NjMsImlhdCI6M
TQ3NDI3OTE2MywianRpIjoiNjY4ODFiMDY4YjI0OWFkOSJ
9.DTfSdMzIIsC0j8z3icRdYO1GaMGl6j1I_2DBjiiHW9vmDz8
OAw8Jh8DpO32fv0vICc0hb4F0QCD3KQnv8GVM73kSYaO
EUwlW0k1TaElxc43_Ocxm1F5IUNZvzlLJ_ksFXGDL_cuadh
VDaiqmhct098ocefuv08TdzRxqYoEqYNo",
"expires_in":3600,
"refresh_token":"eyJhbGctGzv3JOkF0XG5Qx2TlKWIAkF0X.
eyJ0b2tlbi10eXBlIjoiYWNjZXNzLXRva2VuIiwidXNlcm5hb
WUiOiJzbm9vcHkiLCJhbmltYWwiOiJiZWFnbGUiLCJpc3M
iOiJodHRwczovL",
}

64. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2.0 Message with JWT
POST /painter/color/palette HTTP/1.1
Host: api.superbiz.io
Authorization: Bearer eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJ0b2tlbi10eXBlIjoiYWNjZXNzLXR
va2VuIiwidXNlcm5hbWUiOiJzbm9vcHkiLCJhbmltYWwiOiJiZWFnbGUiLCJpc3MiOiJodHRwczovL2RlbW8uc3VwZXJ
iaXouY29tL29hdXRoMi90b2tlbiIsInNjb3BlcyI6WyJ0d2l0dGVyIiwibWFucy1iZXN0LWZyaWVuZCJdLCJleHAiOjE0NzQy
ODA5NjMsImlhdCI6MTQ3NDI3OTE2MywianRpIjoiNjY4ODFiMDY4YjI0OWFkOSJ9.DTfSdMzIIsC0j8z3icRdYO1GaMGl
6j1I_2DBjiiHW9vmDz8OAw8Jh8DpO32fv0vICc0hb4F0QCD3KQnv8GVM73kSYaOEUwlW0k1TaElxc43_Ocxm1F5IUNZ
vzlLJ_ksFXGDL_cuadhVDaiqmhct098ocefuv08TdzRxqYoEqYNo
User-Agent: curl/7.43.0
Accept: */*
Content-Type: application/json
Content-Length: 46
{"color":{"b":0,"g":255,"r":0,"name":"green"}}

65. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2 + JWT
Tokens Sent
3000 TPS
(HTTP+SSL)
IP
whitelisting
0.55 TPS
(refresh token checks)
Password Sent
1000/daily
(HTTP+SSL)
OAuth 2
(LDAP)
4 hops
12000 TPS
backend
3000 TPS
(signature verification)
12000 TPS
(signature verification)

66. JavaOne
#RESTSecurity @dblevins @tomitribe
“Hey, give me all
of Joe’s salary
information.”
“Not a chance!”

67. JavaOne
#RESTSecurity @dblevins @tomitribe
“Hey, give me all
of Joe’s salary
information.”
“Sure thing!”

68. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth 2 + JWT
Valid
Tokens Sent
3000 TPS
(HTTP+SSL)
IP
whitelisting
0.55 TPS
(refresh token checks)
Password Sent
1000/daily
(HTTP+SSL)
(LDAP)
4 hops
12000 TPS
backend
9000 TPS
(signature verification)
12000 TPS
(signature verification)
Invalid
Tokens Sent
6000 TPS
(HTTP+SSL)

69. JavaOne
#RESTSecurity @dblevins @tomitribe
http://connect2id.com/products/nimbus-jose-jwt
Great JWT lib

70. JavaOne
#RESTSecurity @dblevins @tomitribe
HTTP Signatures
(Amazon EC2 style API Security)

71. JavaOne
#RESTSecurity @dblevins @tomitribe
HTTP Signatures
• No “secret” ever hits the wire
• Signs the message itself
• Proves identity
• Prevents message tampering
• Symmetric or Asymmetric signatures
• IETF Draft
• https://tools.ietf.org/html/draft-cavage-http-signatures
• Extremely simple
• Does NOT eliminate benefits of JWT (they’

72. JavaOne
#RESTSecurity @dblevins @tomitribe
Signature Message
POST /painter/color/palette HTTP/1.1
Host: api.superbiz.io
Authorization: Signature keyId=“my-key-name",
algorithm="hmac-sha256",
headers="content-length host date (request-target)”,
signature="j050ZC4iWDW40nVx2oVwBEymXzwvsgm+hKBkuw04b+w="
Date: Mon, 19 Sep 2016 16:51:35 PDT
Accept: */*
Content-Type: application/json
Content-Length: 46
{"color":{"b":0,"g":255,"r":0,"name":"green"}}

73. JavaOne
#RESTSecurity @dblevins @tomitribe
Signature Auth
Password Sent
0 TPS
(HTTP)
Signature (no auth)
3000 TPS
(LDAP or Keystore)
12000 TPS
(HTTP)

74. JavaOne
#RESTSecurity @dblevins @tomitribe
Signature Auth
Password Sent
0 TPS
(HTTP)
Signature Signature
3000 TPS
(LDAP or Keystore)
12000 TPS
(HTTP)

75. JavaOne
#RESTSecurity @dblevins @tomitribe
“Hey, give me all
of Joe’s salary
information.”
“Hey, Larry!
Sure!”

76. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth and Signatures
Password Sent
3000 TPS
(HTTP+SSL)
OAuth 2 Signature
12000 TPS
(HTTP)

77. JavaOne
#RESTSecurity @dblevins @tomitribe
“Hey, give me all
of Joe’s salary
information.”
“Sure thing,
Larry!
Tell Joe I said hi.”

78. JavaOne
#RESTSecurity @dblevins @tomitribe
OAuth and Signatures
Password Sent
3000 TPS
(HTTP+SSL)
OAuth 2 Signature
12000 TPS
(HTTP)
Joe
Larry
Stan

79. JavaOne
#RESTSecurity @dblevins @tomitribe
Observations
• HTTP Signatures the only HTTP friendly approach
• Signatures does not solve the “Identity Load” problem
• OAuth 2 with JWT significantly improves IDP load
• Plain OAuth 2
• HTTP Session-like implications
• OAuth 2 with JWT
• Signed cookie
• Signing key to the future

80. JavaOne
#RESTSecurity @dblevins @tomitribe
Thank You!