Security Analysis on Wireless LAN protocols HORI Yoshiaki - PowerPoint PPT Presentation

Security Analysis on Wireless LAN protocols HORI Yoshiaki hori@csce.kyushu-u.ac.jp Kyushu University / ISIT ETRI-ISIT 1st joint seminar 1

Contents ・ S e c u r i t y a n a l y s i s o n I E E E 8 0 2 . 1 1 i ‐ S h o r t s u m m a r y o f C . H e a n d J . C . M i t c h e l l , “ S e c u r i t y A n a l y s i s a n d I m p r o v e m e n t s f o r I E E E 8 0 2 . 1 1 i , ” N D S S 0 5 , F e b r u a r y 2 0 0 5 ・ S e c u r i t y a n a l y s i s o n M I S p r o t o c o l ‐ Y e t a n o t h e r w i r e l e s s L A N p r o t o c o l b a s e d o n I E E E 8 0 2 . 1 1 p h y s i c a l l a y e r ETRI-ISIT 1st joint seminar 2

Wireless LAN and Security • Wireless LAN (WLAN) – WLAN uses wireless media instead of wired media in order to provide connectivity for a terminal. • A wireless terminal is connected with Access Point (AP) by using of wireless media. – WLAN provides mobility, no wire → WLAN enables easily to build LAN – Currently WLAN become widely deployed. • WLAN security – WLAN security has become a serious concern for many organizations. – Security requirements for a WLAN • Data condidentiality • Integrity • Mutual authentication • Availability ETRI-ISIT 1st joint seminar 3

WLAN security model Wireless terminal Access Point (AP) (Supplicant) (Authenticator) Network Network (Authentication Attack Server) Eaves dropping Adversary ETRI-ISIT 1st joint seminar 4

Wireless Threats (by C. He and J. C. Mitchell, Stanford Univ.) • Wireless Threats – Threat 1: Passive Eavesdropping – Threat 2: Message Injection – Threat 3: Message Deletion and Interception – Threat 4: Masquerading and Malicious AP – Threat 5: Session Hijacking – Threat 6: Man-in-the-Middle – Threat 7: Denial of Service Threats 1, 2, and 3: attack all three type of frames in the Link Layer Threats 4, 5, and 6: defeat mutual authentication Threats 7: interferes with availabilit ETRI-ISIT 1st joint seminar 5

IEEE 802.11i overview ・I E E E s t a n d a r d a p p r o v e d a n d p u b l i s h e d o n J u n e 2 0 0 4 ・D e s i g n e d t o p r o v i d e e n h a n c e d s e c u r i t y i n t h e M e d i a A c c e s s C o n t r o l ( M A C ) l a y e r f o r 8 0 2 . 1 1 w i r e l e s s n e t w o r k s ‐8 0 2 . 1 1 i w o r k s w e l l f o r d a t a c o n f i d e n t i a l i t y , i n t e g r i t y , a n d m u t u a l a u t h e n t i c a t i o n . ・D e f i n e d R o b u s t S e c u r i t y N e t w o r k A s s o c i a t i o n ( R S N A ) w h i c h p r o v i d e s ‐t w o d a t a c o n f i d e n t i a l i t y p r o t o c o l s ; ・T e m p o r a r y K e y I n t e g r i t y P r o t o c o l ( T K I P ) ・C o u n t e r - m o d e / C B C - M A C P r o t o c o l ( C C M P ) w i t h A E S - 1 2 8 ( 1 2 8 b i t K e y a n d 1 2 8 b i t B l o c k s i z e ) ‐A u t h e n t i c a t i o n a n d k e y m a n a g e m e n t p r o t o c o l ・E x t e n s i b l e A u t h e n t i c a t i o n P r o t o c o l ( E A P ) s c h e m e , e . g . E A P - T L S , p r o v i d e s m u t u a l a u t h e n t i c a t i o n . ・4 - w a y h a n d s h a k e e n a b l e s t o s h a r e P a i r w i s e T r a n s i e n t K e y ( P T K ) d e r i v e d f r o m t h e i r P a i r w i s e M a s t e r K e y ( P T K ) . ・A l s o s u p p o r t e d p r e - R S N A f o r c o m p a t i b i l i t y w i t h 8 0 2 . 1 1 ‐W i r e d E q u i v a l e n t P r i v a c y ( W E P ) ETRI-ISIT 1st joint seminar 6

Data confidentiality and Integrity ・ C C M P a p p e a r s t o p r o v i d e s a t i s f a c t o r y d a t a c o n f i d e n t i a l i t y , i n t e g r i t y , a n d r e p l a y p r o t e c t i o n f o r d a t a p a c k e t s a g a i n s t t h r e a t s 1 , 2 a n d 3 . ・ H o w e v e r , t h r e a t s 1 , 2 a n d 3 r e m a i n w i t h m a n a g e m e n t f r a m e s a n d c o n t r o l f r a m e s b e c a u s e t h e s e f r a m e s a r e n e i t h e r e n c r y p t e d n o r a u t h e n t i c a t e d b y t h e l i n k l a y e r e n c r y p t i o n a l g o r i t h m . ETRI-ISIT 1st joint seminar 7

Authentication and Key Management ・I f t h e c o m p l e t e R S N A h a n d s h a k e s a r e p e r f o r m e d , t h e a u t h e n t i c a t i o n a n d k e y m a n a g e m e n t p r o c e s s a p p e a r t o b e s e c u r e . ・H o w e v e r , s i n c e a n a d v e r s a r y c a n i n t e r f e r e w i t h e a r l y s t a g e s i n R S N A h a n d s h a k e s , i t m a y p r e v e n t c o m p l e t i o n o f t h e R S N A . ・S o m e a t t a c k s f o r 8 0 2 . 1 1 i ‐S e c u r i t y l e v e l r o l l b a c k a t t a c k ・B o g u s b e a c o n a n d b o g u s p r o b e r e s p o n s e f r o m a n a u t h e n t i c a t o r ( a c c e s s p o i n t ) , a n d b o g u s a s s o c i a t i o n r e q u e s t . ‐R e f l e c t i o n a t t a c k o n t h e 4 - w a y h a n d s h a k e ETRI-ISIT 1st joint seminar 8

Availability ・ K n o w n D o SA t t a c k s ・ M i c h a e l A l g o r i t h m C o u n t e r m e a s u r e ( i n T K I P ) ‐ N o t a f f e c t e d w i t h C C M P ・ R S N I E ( R S N I n f o r m a t i o n E l e m e n t ) P o i s o n i n g ・ 4 - W a y H a n d s h a k e B l o c k i n g ・ F a i l u r e R e c o v e r y ETRI-ISIT 1st joint seminar 9

Known DoS Attacks ・A n a d v e r s a r y c a n e a s i l y f o r g e t h e m a n a g e m e n t f r a m e s a n d t h e c o n t r o l f r a m e s t o l a u n c h a D o S a t t a c k . ‐T h e m o s t e f f i c i e n t a t t a c k i s t o f o r g e a n d r e p e a t e d l y s e n d D e a u t h e n t i c a t i o n o r D e a s s o c i a t i o n f r a m e s . T h e s e a t t a c k s p e r s i s t e v e n i f 8 0 2 . 1 1 i i s u s e d . ‐T h e r e a r e a l s o s e v e r a l D o Sa t t a c k s t h a t e x p l o i t t h e u n p r o t e c t e d E A P m e s s a g e s i n 8 0 2 . 1 X a u t h e n t i c a t i o n . H o w e v e r , t h e s e v u l n e r a b i l i t i e s f o r t u n a t e l y c a n b e e l i m i n a t e d i n 8 0 2 . 1 1 i b y s i m p l y i g n o r i n g t h e s e m e s s a g e s . ・E A P O L ( E A P o v e r L A N ) - S t a r t , E A P O L - S u c c e s s , E A P O L - F a i l u r e , E A P O L - L o g o f f ETRI-ISIT 1st joint seminar 10

Summary: 802.11i security ・ S a t i s f a c t o r y d a t a c o n f i d e n t i a l i t y , i n t e g r i t y , a n d r e p l a y p r o t e c t i o n f o r d a t a p a c k e t s i s p r o v i d e d b y u s i n g o f C C M P ( A E S ) . ・ M u t u a l a u t h e n t i c a t i o n i s p r o v i d e d b y E A P - T L S a n d 4 - w a y h a n d s h a k e . ・ I n o r d e r t o s u p p o r t a b o v e f e a t u r e s a n d t o k e e p u p p e r c o m p a t i b i l i t y w i t h I E E E 8 0 2 . 1 1 a n d I E E E 8 0 2 . 1 X ( p r e - R S N A ) , w e s h o u l d c o n s i d e r a v a i l a b i l i t y . ETRI-ISIT 1st joint seminar 11