Security in WAP

Sanket Naik, Ameya VardeCS590F Fall 2000

Motivation and Goals• To study the security issues in WAP• To analyze an existing implementation

and implement enhancements• To investigate security holes in the

implementation and WAP in general• To suggest improvements for both

Implementation WAP stack from Kannel (www.kannel.org)

An on-going open source project implementing the WAP stack

No WTLS support WTLS layer from 3ui.com (www.3ui.com) We identified 2 security enhancements:

SSL connection between WAP gateway and Content (HTML) server

Authentication of the WAP gateway by the WAP client

Both missing in WTLS patch from 3ui

Kannel architecture

Security Enhancements

Development tools Platform – Linux OpenSSL crypto library (

http://www.openssl.org) NOKIA WAP Toolkit (

http://www.forum.nokia.com) Simulates a web-enabled NOKIA 7110

phone

WTLS optimizations Why optimize?

Low bandwidth Less processing power Less memory Weaker power supply

The optimizations Abbreviated handshake – using pre-master

secret from previous session Optional steps – Client can send NULL reply to

Certificate request, Anonymous key exchange etc.

The flaws Encryption not truly end-to-end Abbreviated handshake susceptible to replay

attack Chosen plain-text attack: IV for each packet =

Sequence number XOR Original IV DOS attack: Alerts are unauthenticated Man-in-the-middle attack: 40 bit XOR MAC

allows even bit changes Impersonation: Anonymous key exchange

methods allow key generation w/o Authentication (Kannel WTLS has only anonymous key exchange methods!)

Weaker encryption mechanisms due to export regulations

Suggestions WAP specifications

Enforce Client authentication rather than keep it optional

Make WTLS layer mandatory whether people use it or not.

Implementation Provide Gateway authentication in WAP

clients Add stronger algorithms, keys and key

exchange methods to the cipher suites

Conclusions WTLS Specs propose weak security Developers and Manufacturers are

deploying WAP stacks which do not meet even these weak security requirements

Mostly due to lack of security expertise Open source exposing these weaknesses Yet additional code review required Our 2 bits should be checked in soon…