8/12/2019 09 Wlan Security 2005
1/29
WLAN SECURITY
TEAM NAME : Crypto_5
TEAM MEMBERS:
Rajini Ananthoj
Srimani Reddy Gatla
Ishleen Kour
Pallavi MurudkarDeepagandhi Vadivelu
8/12/2019 09 Wlan Security 2005
2/29
Agenda
WLAN and architecture
Security issues faced in WLAN
Basic security of WLAN
solutions for WLAN security
802.1X
EAP Authentication methodsTKIP
CCMP
Intrusion prevention system
Hardware solutions
Things you can do to secure your wireless network
Conclusion References
8/12/2019 09 Wlan Security 2005
3/29
WLAN and Architecture
WLAN: Linking of two
or more computers
without using wires
which uses spreadspectrum technology
based on radio waves.
8/12/2019 09 Wlan Security 2005
4/29
Basic security in WLAN
SSIDs, WEP, and MAC Address Authentication:
Service Set Identifiers: Prevents access by any client device thatdoes not have the SSID.
Open or shared-key authentication, static WEP key: Accesspoint sends the client device a challenge-text packet which clientmust encrypt
Media Access Control authentication: clients MAC addressmatches an address in an authentication table
8/12/2019 09 Wlan Security 2005
5/29
Issues of WLAN Security
Ad- hoc Networks
Policy violation
Identify theft Man in the middle attack
Denial of service attack
8/12/2019 09 Wlan Security 2005
6/29
How WEP works
8/12/2019 09 Wlan Security 2005
7/29
WEP Issues
Uses RC4, a synchronous stream cipher
Does not provide mechanism for sharing Keys
Changing the Initialization Vector (IV) with each packet is
optional
CRC-32 checksum used for message integrity is linear
Concatenates IV directly to the Pre- shared key to produce a key
for RC4
8/12/2019 09 Wlan Security 2005
8/29
What is wrong with 802.11
security
Binds itself to cryptographic algorithm
No security support for handshake
Pre- shared keys One way authentication
Wired equivalent privacy (WEP)
8/12/2019 09 Wlan Security 2005
9/29
Wi-Fi Protected Access(WPA) Interim interoperable standard created by Wi-fi alliance in
response to weaknesses in Wired Equivalent Privacy (WEP) Intermediate measure to take the place of WEP while 802.11i
was prepared
Designed to work with all wireless network interface cards, butnot all first generation wireless access points.
Goals of WPA
To address the issues with WEP encryption through a softwareupgrade
To provide a secure wireless networking solution for small
office/home office (SOHO) wireless users To be forward-compatible with the upcoming IEEE 802.11i
standard
8/12/2019 09 Wlan Security 2005
10/29
Features of WPA
WPA Authentication
Pre-shared key (PSK) every user given the same pass-phrase
less secure
preferred for Personal mode - homes, small offices
IEEE 802.1X authentication
server distributes different keys to each user
enhanced security and authentication
preferred for enterprise mode - business, government, education
8/12/2019 09 Wlan Security 2005
11/29
Encryption
RC4 stream cipher using 128-bit key, 48-bit IV
larger IV defeats Key recovery attack
Key Management
Temporal Key Integrity Protocol (TKIP) - dynamically changesencryption keys for each packet.
Payload Integrity
8 Byte Message integrity code( MIC)
Calculated by algorithm called Michael
Between the payload of the 802.11 frame and the 4-byte ICV
MIC includes a frame counter to prevent replay attacks
8/12/2019 09 Wlan Security 2005
12/29
Thus, WPA makes breaking into a Wireless LAN difficult by
Increasing the size of the keys and IVs
Reducing the number of packets sent with related keys
Adding a secure message verification system
8/12/2019 09 Wlan Security 2005
13/29
IEEE 802.11i / WPA2
An amendment to the 802.11, specifying security mechanisms
for wireless networks
The draft standard was ratified on 24 June 2004
adds stronger encryption, authentication, and key management
strategies
makes use of the Advanced Encryption Standard (AES) blockcipher instead of RC4 stream cipher.
the use of WPA2 needs firmware or driver support of the wireless
host (router or access point) and the wireless client (adapter).
8/12/2019 09 Wlan Security 2005
14/29
Components of WPA2
802.1X Port-Based Network Access Control for
authentication
Counter Mode with CBC-MAC Protocol (CCMP) for
confidentiality, integrity and origin authentication
Temporary Key Integrity Protocol (TKIP) (check)
4-Way Handshake
for Encryption key distribution
8/12/2019 09 Wlan Security 2005
15/29
Comparisons between WPA and WPA2 modes
WPA WPA2
Enterprise Mode
(Business,
Government,Education)
Authentication:
IEEE
802.1X/EAP Encryption:
TKIP/MIC
Authentication:
IEEE
802.1X/EAP Encryption: AES-
CCMP
Personal Mode
(SOHO,Home/Personal)
Authentication:
PSK Encryption:
TKIP/MIC
Authentication:
PSK Encryption: AES-
CCMP
8/12/2019 09 Wlan Security 2005
16/29
IEEE 802.1X
802.1Xis an IEEE standard for port-based Network Access
Control for LANs For WLANs, it is based on the EAP, Extensible Authentication
Protocol
Fullfills the security loopholes of access control, authentication
and key management in 802.11 architecture
Contributes to a solution RSN
The authentication is usually done by a third-party entity, such as
a RADIUS server
8/12/2019 09 Wlan Security 2005
17/29
802.1X Authentication and Access Control
Client -Supplicant
Access point -Authenticator
8/12/2019 09 Wlan Security 2005
18/29
Authenticator deals with controlledand uncontrolledports
8/12/2019 09 Wlan Security 2005
19/29
802.1X Key Management : Broadcast Key Rotation(BKR):
AP periodically broadcasts the WEP shared / root key Mobiles creates session encryption keys by combining
the IV with the broadcast root key
Larger key space: key-hopping cycles through IV
space as well as the session key set Message Integrity
A non-linear MIC prevents bit-flip attacks on encrypted
packets. Implemented on access point and client devices
Adds a few bytes to each packet to make the packetstamper-proof
8/12/2019 09 Wlan Security 2005
20/29
EAP AUTHENTICATION METHODS EAP-MD5: Requires username/password , does not provide dictionary attack
resistance, mutual authentication, or key derivation
Lightweight EAP (LEAP): A username/password combination is sent to aAuthentication Server (RADIUS) for authentication.
EAP-TLS: Creates a TLS session within EAP, between the Supplicant and theAuthentication Server. Both the server and the client(s) need a valid (x509)certificate, and therefore a PKI. This method provides authentication both ways.
EAP-TTLS: Sets up a encrypted TLS-tunnel for safe transport of authenticationdata. Within the TLS tunnel, (any) other authentication methods may be used.
Protected EAP (PEAP):Uses, as EAP-TTLS, an encrypted TLS-tunnel.Supplicant certificates for both EAP-TTLS and EAP-PEAP are optional, butserver (AS) certificates are required
EAP-MSCHAPv2: Requires username/password, and is basically an EAPencapsulation of MS-CHAP-v2 .Usually used inside of a PEAP-encrypted tunnel
8/12/2019 09 Wlan Security 2005
21/29
TKIP - Temporal Key Integrity
Protocol
RC4 stream cipher as in WEP
Keys used for encryption - 128-bit long
Keys used for authentication - 64 bit long
TKIP provides Per-Packet Key Hashing to Mitigate "Weak IV" Attacks:
Each time a wireless station associates to an access point,a new base key is created which is built by hashing basekey with the IV.
Prevention of Collision attacks: Each packet transmittedusing TKIP has a unique 48-bit serial number whichincremented every time a packet is transmitted. Thissolves another problem in WEP, called "collision attacks,"which can occur when the same key is used for twodifferent packets.
8/12/2019 09 Wlan Security 2005
22/29
CCMP (Counter Mode with CBC
MAC Protocol)
CCMP uses the counter mode (CTR) for data confidentialityand the Cipher Block Chaining Message Authentication Code(CBC-MAC) for data integrity.
It uses the Advanced Encryption Standard (AES) algorithm
with a 128-bit key and a 128-bit block size. CCMP provides MIC protection over both the frame body and
nearly the entire header in a MAC frame, which prevents anadversary from exploiting the MAC headers.
CCMP uses a 48-bit Packet Number (PN) to prevent replay
attacks and construct a fresh nonce for each packet Analysis suggests that once CCMP is implemented, an
adversary will not able to break the data confidentiality andintegrity without the knowledge of the key.
8/12/2019 09 Wlan Security 2005
23/29
Dynamic Key Exchange and
Management
802.11i - key derivation/management regime
8/12/2019 09 Wlan Security 2005
24/29
IPS - Intrusion Prevention
System
An intrusion prevention system is a computersecurity device that exercises access control toprotect computers from exploitation.
IPS make access control decisions based onapplication content, rather than IP address or portsas traditional firewalls.
Access points acts as air monitors and dataforwarding devices which allows access points to
communicate real-time information about thewireless domain, including potential security threatsto Wireless LAN controllers
8/12/2019 09 Wlan Security 2005
25/29
Cisco Unified IDS/IPS
The Cisco Unified IDS/IPS is part of the Cisco Self-DefendingNetwork and is the industry's first integrated wireline andwireless security solution.
When an associated client sends malicious traffic through theUnified Wireless network, the Cisco wireline IDS devicedetects the attack and sends shun requests to Unified WLANcontrollers which will then disassociate the client device
8/12/2019 09 Wlan Security 2005
26/29
Some other solutions Smart cards
Beneficial in environments requiring authentication beyondsimple username and password
User certificate and other information are stored on the cards
Portable - users can securely access their networks fromvarious locations
VPN
Provides secure data transmission across public networkinfrastructures.
VPNs employ cryptographic techniques to protect IPinformation as it passes from one network to the next .
Use IPsec Protocol suite for ensuring private communications.
Biometrics
For agencies needing higher levels of security, biometrics suchas fingerprint/palm-print scanners , optical scanner can beintegrated with wireless smart cards
8/12/2019 09 Wlan Security 2005
27/29
Things you can do to secure your wireless
network.
Change the default Admin password on your Access Point
Check / Update the firmware for your Wireless Access Point anddrivers for your Wireless Adapter.
Use the highest level of WEP/WPA (WPA2/802.11i strongly
preferred) -- Use decent keys. Authenticate wireless users with protocols like 802.1X, RADIUS,
EAP (including EAP-PAX, EAP-PSK, EAP-TLS, EAP-TTLS,PEAP, and EAP-SIM).
Use strong encryption for all applications you use over the
wireless network, e.g., use SSH and TLS/HTTPS. Encrypt wireless traffic using a VPN (Virtual Private Network),
e.g. using IPSEC or other VPN solutions.
8/12/2019 09 Wlan Security 2005
28/29
Conclusion
The optimal security solution for WLAN
involves a combination of security
technologies.
A detailed threat risk assessment and
analysis is essential to determine which
security measures or combination of
measures are the most effective.
8/12/2019 09 Wlan Security 2005
29/29
References
en.wikipedia.org/wiki/Wi-Fi_Protected_Access
en.wikipedia.org/wiki/WPA2
http://en.wikipedia.org/wiki/IEEE_802.1x
en.wikipedia.org/wiki/TKIP http://www.networkworld.com/reviews/2004/1004wir
elesstkip.html
http://tldp.org/HOWTO/html_single/8021X-
HOWTO/#p8021x www.wi-fiplanet.com/tutorials/article.php/953561
www.drizzle.com/~aboba/IEEE/
http://en.wikipedia.org/wiki/IEEE_802.1xhttp://tldp.org/HOWTO/html_single/8021X-HOWTO/http://tldp.org/HOWTO/html_single/8021X-HOWTO/http://www.wi-fiplanet.com/tutorials/article.php/953561http://www.drizzle.com/~aboba/IEEE/http://www.drizzle.com/~aboba/IEEE/http://www.wi-fiplanet.com/tutorials/article.php/953561http://www.wi-fiplanet.com/tutorials/article.php/953561http://www.wi-fiplanet.com/tutorials/article.php/953561http://tldp.org/HOWTO/html_single/8021X-HOWTO/http://tldp.org/HOWTO/html_single/8021X-HOWTO/http://tldp.org/HOWTO/html_single/8021X-HOWTO/http://en.wikipedia.org/wiki/IEEE_802.1xTop Related