Presentation of a paper at ARES 2007 conference. Security architecture to prevent phishing attacks.

1. RuhR-Universität Bochum
Compartmented Security for Browsers
-
Or How to Thwart a Phisher with Trusted Computing
Sebastian Gajek, Ahmad-Reza Sadeghi, Christian Stüble, Marcel Winandy
Horst Görtz Institute for IT Security
Ruhr-University Bochum, Germany
ARES 2007
2nd International Conference on Availability, Reliability and Security
Vienna, 10-13 April 2007

2. RuhR-Universität Bochum
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 2

3. RuhR-Universität Bochum
"Classical" Phishing
Costumers
(e.g., bank)
…….
credentials
credentials (e.g., username,password)
Adversary A Collection Server
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 3

4. RuhR-Universität Bochum
Malware Phishing
Costumers
(e.g., bank)
…….
credentials
Adversary A Collection Server
Tailored to specific
services, such as
domestic banks
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 4

5. RuhR-Universität Bochum
Reasons for Success
● Strong assumptions on ordinary users
● Legacy flaws of Internet technology (e.g. DNS)
● Vulnerabilities of underlying computing platform
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 5

6. RuhR-Universität Bochum
Existing approaches
● Browser-based
● Server-based
● Operating System based
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 6

7. RuhR-Universität Bochum
Browser-based approaches
● White lists / black lists
● Heuristic checks
● Blinking browser boundaries
● Logo-type certificates
● Wallets
F extra functionality
Browser
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 7

8. RuhR-Universität Bochum
Browser-based approaches
● White lists / black lists
● Heuristic checks
● Blinking browser boundaries
● Logo-type certificates
● Wallets
Malware
Browser F Phishing !?
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 8

9. RuhR-Universität Bochum
Server-Based Approaches
● User-friendly authentication protocols
● Password-augmented SSL protocol
● Trusted device augmented SSL protocol
F extra functionality
Client Server
Client
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 9

10. RuhR-Universität Bochum
Server-Based Approaches
● User-friendly authentication protocols
● Password-augmented SSL protocol
● Trusted device augmented SSL protocol
F
Client Server
Client
Malware
Phishing !?
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 10

11. RuhR-Universität Bochum
OS-Based Approaches
● Isolation
● Integrity Verification
● Secure GUI
● Virtualization
Example: Tahoma BOS
Browser Browser Browser
VM VM VM
VMM
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 11

12. RuhR-Universität Bochum
OS-Based Approaches
● Isolation
● Integrity Verification
● Secure GUI
● Virtualization
Example: Tahoma BOS
Browser Browser Browser
Classical
VM VM VM
Phishing !?
VMM
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 12

13. Idea:
Combination
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 13

14. RuhR-Universität Bochum
Our Approach
● Trusted wallet: Let the system...
– authenticate legitimate service sites
– control and perform the user authentication
● Compartmentalization: Isolate browser / wallet
● Trusted execution environment:
– Security kernel
– Trusted Computing
– Virtualization
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 14

15. RuhR-Universität Bochum
Basic Architecture
authentication data
compartment
service virtual real
usage Browser network Wallet­ network Service
U
Proxy P
Legacy OS
Security Kernel
Hardware
(Trusted Computing Support)
System S
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16. RuhR-Universität Bochum
Wallet-Proxy
authenticate UW
update_proxy WB
use_service U↔B use_service B↔W authenticate WP
Browser Wallet­Proxy
U use_service P↔W P
B W
SSL secured channel
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 16

17. RuhR-Universität Bochum
Wallet-Proxy
Setup
login
data
authenticate UW
update_proxy WB
use_service U↔B use_service B↔W authenticate WP
Browser Wallet­Proxy
U use_service P↔W P
B W
SSL secured channel
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 17

18. RuhR-Universität Bochum
Wallet-Proxy
Setup
login
data
authenticate UW
update_proxy WB
use_service U↔B use_service B↔W authenticate WP
Browser Wallet­Proxy
U use_service P↔W P
B W
SSL secured channel
Call
service
site
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 18

19. RuhR-Universität Bochum
Wallet-Proxy
Setup
login
data
authenticate UW
update_proxy WB
use_service U↔B use_service B↔W authenticate WP
Browser Wallet­Proxy
U use_service P↔W P
B W
SSL secured channel
Call Insert
service login
site data
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 19

20. RuhR-Universität Bochum
Wallet-Proxy
Setup
login
data
authenticate UW
update_proxy WB
use_service U↔B use_service B↔W authenticate WP
Browser Wallet­Proxy
U use_service P↔W P
B W
SSL secured channel
Call Insert
service login Authenticate
site data site and user
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 20

21. RuhR-Universität Bochum
Setup Procedure
● "Two-factor authentication"
– User receives credentials out-of-band
● username, password (uid, pwdid), URLid of website, and ack.code
– Wallet blocks login forms in Browser
– User has to enter credentials in Wallet
– Wallet performs login procedure
– User enters acknowledgement code in Browser
● "One-factor authentication"
– User has to register online at website
– Wallet blocks login forms in Browser
– User has to enter credentials in Wallet
– Wallet links password to website
● pwdid := hash(pwdiduser || r), r is random value
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 21

22. RuhR-Universität Bochum
Trusted Components
Wallet­Proxy network connection
user interface
W
input / output load / store data
start
start Compartment start Storage
U Secure GUI
Manager Manager
sealing / unsealing
measurement
TPM Net P
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 22

23. RuhR-Universität Bochum
Trusted Components
Wallet­Proxy network connection
user interface
W
input / output load / store data
start
start Compartment start Storage
U Secure GUI
Manager Manager
sealing / unsealing
measurement
TPM Net P
Trusted
path
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 23

24. RuhR-Universität Bochum
Trusted Components
Wallet­Proxy network connection
user interface
W
input / output load / store data
start
start Compartment start Storage
U Secure GUI
Manager Manager
sealing / unsealing
measurement
TPM Net P
Trusted
path
System
integrity
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 24

25. RuhR-Universität Bochum
Secure Booting
OS
OS Loader TPM
BIOS
CRTM PCRs
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 25

26. RuhR-Universität Bochum
Secure Booting
Proxy Wallet
W
start
start Compartment start Storage
Secure GUI
Manager Manager
OS
OS Loader TPM
BIOS
CRTM PCRs
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 26

27. RuhR-Universität Bochum
Secure Booting
Proxy Wallet Seal Wallet data to
W
platform configuration
start
start Compartment start Storage
Secure GUI
Manager Manager
OS
OS Loader TPM
BIOS
CRTM PCRs
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 27

28. RuhR-Universität Bochum
Implementation
Isolation
{untrusted } {trusted }
Wallet
Email Browser
Proxy
Application Layer
Compartment Compartment
Trusted Software Layer
Security Kernel
Hypervisor Layer
Hardware TPM Hardware Layer
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 28

29. RuhR-Universität Bochum
Implementation
Isolation
{untrusted } {trusted }
Wallet
Email Browser
Proxy
Application Layer
Compartment Compartment
Secure GUI Trusted Software Layer
Compartment Mgr Storage Mgr
Security Kernel
Input Video Net TDD Disk
Hypervisor Layer
L4 Microkernel
Hardware TPM Hardware Layer
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 29

30. RuhR-Universität Bochum
Ongoing and Future Work
● Web form scanner
– Currently improving and enhancing implementation
● System updates (property-based attestation)
– Currently working on PbA implementation
● What about additional user attributes?
– e.g. address, age, credit card number, etc.
● Usability
– Secure GUI ("mGUI")
– Proxy-Wallet
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 30

31. RuhR-Universität Bochum
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 31

32. RuhR-Universität Bochum
Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 32

33. RuhR-Universität Bochum
Questions ?
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34. backup
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35. Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 35

36. Marcel Winandy Compartmented Security for Browsers (ARES 2007) 2007-04-10 36