Enhancing web browsing security on public terminals using mobile composition

Abstract

This paper presents an architecture that affords mobile users greater trust and security when browsing the internet (e.g., when making personal/financial transactions) from public terminals at Internet Cafes or other unfamiliar locations. This is achieved by enabling web applications to split their client-side pages across a pair of browsers: one untrusted browser running on a public PC and one trusted browser running on the user's personal mobile device, composed into a single logical interface through a local connection, wired or wireless. Information entered via the personal device's keypad cannot be read by the PC, thwarting PC-based key-loggers. Similarly, information displayed on the personal device's screen is also hidden from the PC, preserving the confidentiality and integrity of security-critical data even in the presence of screen grabbing attacks and compromised PC browsers. We present a security policy model for split-trust web applications that defends against a range of crimeware-based attacks, including those based on active-injection (e.g. inserting malicious packets into the network or spoofing user-input events). Performance results of a prototype split-trust implementation are presented, using a commercially available cell phone as a trusted personal device.