Towards Multicolored Computing - Compartmented Security to Prevent Phishing Attacks Sebastian Gajek, Ahmad-Reza Sadeghi, Christian St¨ uble, and Marcel Winandy Horst G¨ortz Institute for IT Security Ruhr-University Bochum Universit¨ atsstr. 150, D-44780 Bochum, Germany sebastian.gajek@nds.rub.de, sadeghi@crypto.rub.de, stueble@acm.org, winandy@ieee.org Abstract Identity theft through phishing attacks has fostered to a major concern of Internet users. Classical phishing attacks aim at luring the user to a faked web site to disclose personal information. Various solutions have been proposed against this kind of at- tack. However, these solutions can hardly counter the new generation of sophisticated malware phish- ing attacks designed to target certain services. This paper aims at making the first steps towards the design and implementation of an open source and interoperable security architecture that pre- vents both classical and malware phishing attacks. Our approach is based on the ideas of (i) the multi- colored computing (e.g., red for the risky and green for the trusted domain), and (ii) a trusted wallet for storing credentials and authenticating sensitive services. Our solution requires no special care from users for identifying the right web sites while the disclosure of credentials is strictly controlled. We present the main idea of how to integrate countermeasures against Phishing and malware into one sound security architecture. Our approach es- tablishes compartmented security for mounting iso- lated applications, provides a secure graphical user interface to configure sensitive applications, and performs secure booting to preserve the system in- tegrity. We also give hints on how to implement this architecture efficiently by utilizing trusted comput- ing functionality and virtualization. 1 Introduction The Internet and its underlying infrastructure might constitute the most complex IT system ever built. On the one hand, this huge platform offers us many opportunities to access information, gain knowledge and set up a variety of business mod- els with sophisticated functional and security re- quirements. On the other hand, it also bears many risks that can be exploited by adversaries who mis- use this powerful medium driven by various moti- vations. In this context, the issue of identity theft has become a subject of great concern in the recent years: Since password-based user authentication es- tablished on the Internet to grant users access to security critical services, identity theft and fraud attracted attackers [37]. Hence, phishing—a collo- quial abbreviation of password fishing —has become a prominent attack. Whereas classical phishing at- tacks primarily used rogue emails to lure unwary users to faked web sites where they revealed per- sonal information (e.g., passwords, credit card num- bers, transaction numbers), current attacks have become advanced in their number and technical so- phistication [2, 16, 20]. This type of phishing does not solely address the weaknesses of careless Inter- net users, but also exploits vulnerabilities of the underlying computing platforms and takes advan- tage of legacy flaws of Internet technologies: Hos- tile profiling addresses specific email recipients to more precisely mount classical phishing attacks [10], pharming compromises DNS servers to resolve do- main name requests to phishing sites [2], and mal- ware phishing infiltrates customers’ computers to log their password stroking using special malicious programs [24]. The most dominant reason for the proliferation of phishing attacks is that strong assumptions and requirements are made on the ability of ordinary In- ternet users when accessing sensitive services (see, e.g., [18]). Studies point out that ordinary Inter- net users often do not distinguish legitimate from faked web sites and do not understand security in- dicators [31]. Thus, they are vulnerable to classi- cal phishing attacks: To reliably authenticate a web site, the user has to verify the domain name, ‘https’ in the URL, and the server certificate. However, or- dinary Internet users are unfamiliar with the mean- ing of SSL. This is in particular true for common 1