Governments and regulatory bodies have recognized investment scams as a prevalent form of cryptocurrency fraud. These scams typically use professional-looking websites to lure unsuspecting victims with promises of unrealistically high returns. In this paper, we introduce Crimson, a distributed system designed to continuously detect cryptocurrency investment scam websites as they are created in the wild. During the first 8 months of 2024, Crimson processed approximately 6 billion domain names and classified 43,572 unique cryptocurrency investment scam websites in real-time. Beyond detection, we provide insights into the design and infrastructure of these websites that can help users recognize scam patterns and assist hosting providers in detecting and blocking such sites. Furthermore, we investigate the inclusion of our detected scam websites in block-lists used by popular web browsers and applications, finding that the vast majority of these websites were absent. On the financial side, by analyzing the transactions incoming to scammer wallets on 6.7% of the sites detected by Crimson, we observe an estimated lower bound of 2.04M USD in losses due to cryptocurrency investment scams.

Web vulnerability scanners (WVS) are an indispensable tool for penetration testers and developers of web applications, allowing them to identify and fix low-hanging vulnerabilities before they are discovered by attackers. Unfortunately, malicious actors leverage the very same tools to identify and exploit vulnerabilities in third-party websites. Existing research in the WVS space is largely concerned with how many vulnerabilities these tools can discover, as opposed to trying to identify the tools themselves when they are used illicitly.

The modern web is a collection of remote resources that are identified by their location and composed of interleaving networks of trust. Supply chain attacks compromise the users of a target domain by leveraging its often large set of trusted third parties who provide resources such as JavaScript. The ubiquity of JavaScript, paired with its ability to execute arbitrary code on client machines, makes this particular web resource an ideal vector for supply chain attacks. Currently, there exists no robust method for users browsing the web to verify that the script content they receive from a third party is the expected content.

Digital media (including websites and online social networks) facilitate the broadcasting of news via flexible and personalized channels. Unlike conventional newspapers which become “read-only” upon publication, online news sources are free to arbitrarily modify news headlines after their initial release. The motivation, frequency, and effect of post-publication headline changes are largely unknown, with no offline equivalent from where researchers can draw parallels.

Illicit website owners frequently rely on traffic distribution systems (TDSs) operated by less-than-scrupulous advertising networks to acquire user traffic. While researchers have described a number of case studies on various TDSs or the businesses they serve, we still lack an understanding of how users are differentiated in these ecosystems, how different illicit activities frequently leverage the same advertisement networks and, subsequently, the same malicious advertisers. We design ODIN (Observatory of Dynamic Illicit ad Networks), the first system to study cloaking, user differentiation and business integration at the same time in four different types of traffic sources: typosquatting, copyright-infringing movie streaming, ad-based URL shortening, and illicit online pharmacy websites.

In this paper, we investigate to what extent the page modifications that make browser extensions fingerprintable are necessary for their operation. We characterize page modifications that are completely unnecessary for the extension's functionality as extension bloat. By analyzing 58,034 extensions from the Google Chrome store, we discovered that 5.7% of them were unnecessarily identifiable because of extension bloat. To protect users against unnecessary extension fingerprinting due to bloat, we describe the design and implementation of an in-browser mechanism that provides coarse-grained access control for extensions on all websites. The proposed mechanism and its built-in policies, does not only protect users from fingerprinting, but also offers additional protection against malicious extensions exfiltrating user data from sensitive websites.

An event that is rarely considered by technical users and laymen alike is that of a domain name expiration. The massive growth in the registration of domain names is matched by massive numbers of domain expirations, after which domains are made available for registration again. While the vast majority of expiring domains are of no value, among the hundreds of thousands of daily expirations, there exist domains that are clearly valuable, either because of their lexical composition, or because of their residual trust. In this paper, we investigate the dynamics of domain dropcatching where companies, on behalf of users, compete to register the most desirable domains as soon as they are made available and then auction them off to the highest bidder. Using a data-driven approach, we monitor the expiration of 28 million domains over the period of nine months, collecting domain features, WHOIS records, and crawling the registered domains on a regular basis to uncover the purpose for which they were re-registered (caught). Among others, we find that on average, only 10% of the expired (dropped) domains are caught with the vast majority of the re-registrations happening on the day they are released. We investigate the features that make some domains more likely to be caught than others and discover that a domain that was malicious at the time of its expiration is twice as likely to be caught than the average domain. Moreover, previously-malicious domains are significantly more likely to be reused for malicious purposes than previously benign domains. We identify three types of users who are interested in purchasing dropped domains, ranging from freelancers who purchase one or two domains to professionals who invest more than $115K purchasing dropped domains in only three months. Finally, we observe that less than 11% were used to host web content with the remaining domains used either by speculators, or by malicious actors.

Technical Support Scams (TSS), which combine online abuse with social engineering over the phone channel, have persisted despite several law enforcement actions. Although recent research has provided important insights into TSS, these scams have now evolved to exploit ubiquitously used online services such as search and sponsored advertisements served in response to search queries. We use a data-driven approach to understand search-and-ad abuse by TSS to gain visibility into the online infrastructure that facilitates it. By carefully formulating tech support queries with multiple search engines, we collect data about both the support infrastructure and the websites to which TSS victims are directed when they search online for tech support resources. We augment this with a DNS-based amplification technique to further enhance visibility into this abuse infrastructure. By analyzing the collected data, we provide new insights into search-and-ad abuse by TSS and reinforce some of the findings of earlier research. Further, we demonstrate that tech support scammers are (1) successful in getting major as well as custom search engines to return links to websites controlled by them, and (2) they are able to get ad networks to serve malicious advertisements that lead to scam pages. Our study period of approximately eight months uncovered over 9,000 TSS domains, of both passive and aggressive types, with minimal overlap between sets that are reached via organic search results and sponsored ads. Also, we found over 2,400 support domains which aid the TSS domains in manipulating organic search results. Moreover, to our surprise, we found very little overlap with domains that are reached via abuse of domain parking and URL-shortening services which was investigated previously. Thus, investigation of search-and-ad abuse provides new insights into TSS tactics and helps detect previously unknown abuse infrastructure that facilitates these scams.

To better understand the demographics of their visitors and their paths through their websites, the vast majority of modern website owners make use of third-party analytics platforms, such as, Google Analytics and ClickTale. Given that all the clients of a third-party analytics platform report to the same server, the tracking requests need to contain identifiers that allow the analytics server to differentiate between their clients. In this paper, we analyze the analytics identifiers utilized by eighteen different third-party analytics platforms and show that these identifiers enable the clustering of seemingly unrelated websites as part of a common third-party analytics account (i.e. websites whose analytics are managed by a single person or team). We focus our attention on malicious websites that also utilize third-party web analytics and show that threat analysts can utilize web analytics to both discover previously unknown malicious pages in a threat-agnostic fashion, as well as to cluster malicious websites into campaigns. We build a system for automatically identifying, isolating, and querying analytics identifiers from malicious pages and use it to discover an additional 11K live domains that use analytics associated with malicious pages. We show how our system can be used to improve the coverage of existing blacklists, discover previously unknown phishing campaigns, identify malicious binaries and Android apps, and even aid in attribution of malicious domains with protected WHOIS information.

Users on Twitter are commonly identified by their profile names. These names are used when directly addressing users on Twitter, are part of their profile page URLs, and can become a trademark for popular accounts, with people referring to celebrities by their real name and their profile name, interchangeably. Twitter, however, has chosen to not permanently link profile names to their corresponding user accounts. In fact, Twitter allows users to change their profile name, and afterwards makes the old profile names available for other users to take.

Users have come to rely on browser extensions to realize features that are not implemented by browser vendors. Extensions offer users the ability to, among others, block ads, de-clutter websites, enrich pages with third-party content, and take screenshots. At the same time, because of their privileged position inside a user's browser, extensions have access to content and functionality that is not available to webpages, such as, the ability to conduct and read cross-origin requests, as well as get access to a browser's history and cookie jar.

Web shells are malicious scripts that attackers upload to a compromised web server in order to remotely execute arbitrary commands, maintain their access, and elevate their privileges. Despite their high prevalence in practice and heavy involvement in security breaches, web shells have never been the direct subject of any study. In contrast, web shells have been treated as malicious blackboxes that need to be detected and removed, rather than malicious pieces of software that need to be analyzed and, in detail, understood. In this paper, we report on the first comprehensive study of web shells. By utilizing different static and dynamic analysis methods, we discover and quantify the visible and invisible features offered by popular malicious shells, and we discuss how attackers can take advantage of these features. For visible features, we find the presence of password bruteforcers, SQL database clients, portscanners, and checks for the presence of security software installed on the compromised server. In terms of invisible features, we find that about half of the analyzed shells contain an authentication mechanism, but this mechanism can be bypassed in a third of the cases. Furthermore, we find that about a third of the analyzed shells perform homephoning, i.e., the shells, upon execution, surreptitiously communicate to various third parties with the intent of revealing the location of new shell installations. By setting up honeypots, we quantify the number of third-party attackers benefiting from shell installations and show how an attacker, by merely registering the appropriate domains, can completely take over all installations of specific vulnerable shells.

Researchers have shown that, in recent years, unwanted web tracking is on the rise, with browser-based fingerprinting being adopted by more and more websites as a viable alternative to third-party cookies. In this paper we propose PriVaricator, a solution to the problem of browser-based fingerprinting. A key insight is that when it comes to web tracking, the real problem with fingerprinting is not uniqueness of a fingerprint, it is linkability, i.e., the ability to connect the same fingerprint across multiple visits. Thus, making fingerprints non-deterministic also makes them hard to link across browsing sessions. In PriVaricator we use the power of randomization to "break" linkability by exploring a space of parameterized randomization policies. We evaluate our techniques in terms of being able to prevent fingerprinting and not breaking existing (benign) sites. The best of our randomization policies renders all the fingerprinters we tested ineffective, while causing minimal damage on a set of 1000 Alexa sites on which we tested, with no noticeable performance overhead.

URL shortening services facilitate the need of exchanging long URLs using limited space, by creating compact URL aliases that redirect users to the original URLs when followed. Some of these services show advertisements (ads) to link-clicking users and pay a commission of their advertising earnings to link-shortening users.

Over the last fifteen years, several types of attacks against domain names and the companies relying on them have been observed. The well-known cybersquatting of domain names gave way to typosquatting, the abuse of a user's mistakes when typing a URL in her browser's address bar. Recently, a new attack against domain names surfaced, namely bitsquatting. In bitsquatting, an attacker leverages random bit-errors occurring in the memory of commodity computers and smartphones, to redirect Internet traffic to attacker-controlled domains.