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Ali Zand

Ali Zand

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Google Publications
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    Preview abstract As technologies to defend against phishing and malware often impose an additional financial and usability cost on users (such as security keys), a question remains as to who should adopt these heightened protections. We measure over 1.2 billion email-based phishing and malware attacks against Gmail users to understand what factors place a person at heightened risk of attack. We find that attack campaigns are typically short-lived and at first glance indiscriminately target users on a global scale. However, by modeling the distribution of targeted users, we find that a person's demographics, location, email usage patterns, and security posture all significantly influence the likelihood of attack. Our findings represent a first step towards empirically identifying the most at-risk users. View details
    Preview abstract In this paper, we present the first longitudinal measurement study of the underground ecosystem fueling credential theft and assess the risk it poses to millions of users. Over the course of March, 2016--March, 2017, we identify 788,000 potential victims of off-the-shelf keyloggers; 12.4 million potential victims of phishing kits; and 1.9 billion usernames and passwords exposed via data breaches and traded on blackmarket forums. Using this dataset, we explore to what degree the stolen passwords---which originate from thousands of online services---enable an attacker to obtain a victim's valid email credentials---and thus complete control of their online identity due to transitive trust. Drawing upon Google as a case study, we find 7--25\% of exposed passwords match a victim's Google account. For these accounts, we show how hardening authentication mechanisms to include additional risk signals such as a user's historical geolocations and device profiles helps to mitigate the risk of hijacking. Beyond these risk metrics, we delve into the global reach of the miscreants involved in credential theft and the blackhat tools they rely on. We observe a remarkable lack of external pressure on bad actors, with phishing kit playbooks and keylogger capabilities remaining largely unchanged since the mid-2000s. View details
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