1. Security issues in public access WLAN architectures
March 2002
Security issues in public access WLAN architectures
Mats Näslund, Stefan Rommer
Ericsson
Mats Näslund & Stefan Rommer, Ericsson

2. Traditional WLAN Environment
March 2002
sjkasjhd
March 2002
Traditional WLAN Environment
Corporate
Intranet
protected
Crypto
Protection AP AP
- Trusted environment
- No charging
Mats Näslund & Stefan Rommer, Ericsson
John Doe, His Company

3. Public Access WLAN Environment
March 2002
sjkasjhd
March 2002
Public Access WLAN Environment
HOME
AIRPORT
WLAN
“HOT-SPOTS”
3G Roaming Net
HOTEL
OFFICE/WORK
PUBLIC
AREA
Mats Näslund & Stefan Rommer, Ericsson
John Doe, His Company

4. Corporate Network or Service Network
March 2002
Access Scenario
UTRAN
RNC
Node B
SGSN
GGSN/FA Gn Iu
Gr(MAP)
HSS
AuC
HLR Gi
3GPP
Core Network
Access Server/HA
AAA
Subscriber Mgmt
Charging/Billing
AAA
Corporate Network or Service Network
Wx (Diameter) IP AP
WSN/FA
AAA
Roaming Partner
Signalling and User Data
Signalling Data
Protection AP
WRAN
HOTSPOT
Could be highly untrusted!
Mats Näslund & Stefan Rommer, Ericsson

5. Security End-points Protected! (Physically secured) Confidentiality
March 2002
Security End-points
WRAN AP
WSN/FA
Protected! (Physically secured) AP
Confidentiality
(soon: integrity)
No protection! Could be tampered with.
No protection!
Robust charging requires
at least integrity protection.
Mats Näslund & Stefan Rommer, Ericsson

6. WLAN Public Access Public access is an important WLAN scenario.
March 2002
WLAN Public Access
Public access is an important WLAN scenario.
Security in public scenarios should be important to TGi.
How can TGi secure traffic in the AP and the connecting cable?
Make it possible to move the security endpoint into the wired network
Other (less secure) possibilities
AP in tampering-proof box?
Make physical access to Ethernet cable impossible?
More?
Mats Näslund & Stefan Rommer, Ericsson

7. Moving the security endpoint
March 2002
Moving the security endpoint
It should be possible to signal the AP not to perform data authentication (a node inside the wired network will check integrity).
Optionally, decryption and the whole security association could be moved.
Consequences:
Higher security in public scenarios.
Transparent for RSN-capable mobile nodes.
Little point in using OCB, separate MIC preferred.
Simpler/legacy APs (without RSN) could be used.
Have to be solved:
Signaling between AP and network node, fragmentation, etc.
Mats Näslund & Stefan Rommer, Ericsson