An official website of the United States government
Global Internet users increasingly rely on virtual private network (VPN) services to preserve their privacy, circumvent censorship, and access geo-filtered content. Due to their own lack of technical sophistication and the opaque nature of VPN clients, however, the vast majority of users have limited means to verify a given VPN service’s claims along any of these dimensions. We design an active measurement system to test various infrastructural and privacy aspects of VPN services and evaluate 62 commercial providers. Our results suggest that while commercial VPN services seem, on the whole, less likely to intercept or tamper with user traffic than other, previously studied forms of traffic proxying, many VPNs do leak user traffic—perhaps inadvertently—through a variety of means. We also find that a non-trivial fraction of VPN providers transparently proxy traffic, and many misrepresent the physical location of their vantage points: 5–30% of the vantage points, associated with 10% of the providers we study, appear to be hosted on servers located in countries other than those advertised to users.
more »
« less
CalcuLatency: Leveraging Cross-Layer Network Latency Measurements to Detect Proxy-Enabled Abuse
Efforts from emerging technology companies aim to democratize the ad delivery ecosystem and build systems that are privacy-centric and even share ad revenue benefits with their users. Other providers offer remuneration for users on their platform for interacting with and making use of services. But these efforts may suffer from coordinated abuse efforts aiming to defraud them. Attackers can use VPNs and proxies to fabricate their geolocation and earn disproportionate rewards. Balancing proxy-enabled abuse-prevention techniques with a privacy-focused business model is a hard challenge. Can service providers use minimal connection features to infer proxy use without jeopardizing user privacy? In this paper, we build and evaluate a solution, CalcuLatency, that incorporates various network latency measurement techniques and leverage the application-layer and network-layer differences in roundtrip-times when a user connects to the service using a proxy. We evaluate our four measurement techniques individually, and as an integrated system using a two-pronged evaluation. CalcuLatency is an easy-to-deploy, open-source solution that can serve as an inexpensive first- step to label proxies.
more »
« less
- Award ID(s):
- 2237552
- PAR ID:
- 10587802
- Publisher / Repository:
- USENIX Association
- Date Published:
- ISBN:
- 978-1-939133-44-1
- Format(s):
- Medium: X
- Location:
- Philadelphia PA USA
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
null (Ed.)Residential proxy has emerged as a service gaining popularity recently, in which proxy providers relay their customers’ network traffic through millions of proxy peers under their control. We find that many of these proxy peers are mobile devices, whose role in the proxy network can have significant security implications since mobile devices tend to be privacy and resource-sensitive. However, little effort has been made so far to understand the extent of their involvement, not to mention how these devices are recruited by the proxy network and what security and privacy risks they may pose. In this paper, we report the first measurement study on the mobile proxy ecosystem. Our study was made possible by a novel measurement infrastructure, which enabled us to identify proxy providers, to discover proxy SDKs (software development kits), to detect Android proxy apps built upon the proxy SDKs, to harvest proxy IP addresses, and to understand proxy traffic. The information collected through this infrastructure has brought to us new understandings of this ecosystem and important security discoveries. More specifically, 4 proxy providers were found to offer app developers mobile proxy SDKs as a competitive app monetization channel, with $50K per month per 1M MAU (monthly active users). 1,701 Android APKs (belonging to 963 Android apps) turn out to have integrated those proxy SDKs, with most of them available on Google Play with at least 300M installations in total. Furthermore, 48.43% of these APKs are flagged by at least 5 anti-virus engines as malicious, which could explain why 86.60% of the 963 Android apps have been removed from Google Play by Oct 2019. Besides, while these apps display user consent dialogs on traffic relay, our user study indicates that the user consent texts are quite confusing. We even discover a proxy SDK that stealthily relays traffic without showing any notifications. We also captured 625K cellular proxy IPs, along with a set of suspicious activities observed in proxy traffic such as ads fraud. We have reported our findings to affected parties, offered suggestions, and proposed the methodologies to detect proxy apps and proxy traffic.more » « less
-
Privacy technologies support the provision of online services while protecting user privacy. Cryptography lies at the heart of many such technologies, creating remarkable possibilities in terms of functionality while offering robust guarantees of data confidential- ity. The cryptography literature and discourse often represent that these technologies eliminate the need to trust service providers, i.e., they enable users to protect their privacy even against untrusted service providers. Despite their apparent promise, privacy technolo- gies have seen limited adoption in practice, and the most successful ones have been implemented by the very service providers these technologies purportedly protect users from. The adoption of privacy technologies by supposedly adversarial service providers highlights a mismatch between traditional models of trust in cryptography and the trust relationships that underlie deployed technologies in practice. Yet this mismatch, while well known to the cryptography and privacy communities, remains rela- tively poorly documented and examined in the academic literature— let alone broader media. This paper aims to fill that gap. Firstly, we review how the deployment of cryptographic tech- nologies relies on a chain of trust relationships embedded in the modern computing ecosystem, from the development of software to the provision of online services, that is not fully captured by tra- ditional models of trust in cryptography. Secondly, we turn to two case studies—web search and encrypted messaging—to illustrate how, rather than removing trust in service providers, cryptographic privacy technologies shift trust to a broader community of secu- rity and privacy experts and others, which in turn enables service providers to implicitly build and reinforce their trust relationship with users. Finally, concluding that the trust models inherent in the traditional cryptographic paradigm elide certain key trust relation- ships underlying deployed cryptographic systems, we highlight the need for organizational, policy, and legal safeguards to address that mismatch, and suggest some directions for future work.more » « less
-
Network security devices intercept, analyze and act on the traffic moving through the network to enforce security policies. They can have adverse impact on the performance, functionality, and privacy provided by the network. To address this issue, we propose a new approach to network security based on the concept of short-term on-demand security exceptions. The basic idea is to bring network providers and (trusted) users together by (1) implementing coarse-grained security policies in the traditional way using conventional in-band security approaches, and (2) handling special cases policy exceptions in the control plane using user/application-supplied information. By divulging their intent to network providers, trusted users can receive better service. By allowing security exceptions, network providers can focus inspections on general (untrusted) traffic. We describe the design of an on-demand security exception mechanism and demonstrate its utility using a prototype implementation that enables high-speed big-data transfer across campus networks. Our experiments show that the security exception mechanism can improve the throughput of flows by trusted users significantly.more » « less
-
Joe Calandrino and Carmela Troncoso (Ed.)As service providers are moving to the cloud, users are forced to provision sensitive data to the cloud. Confidential computing leverages hardware Trusted Execution Environment (TEE) to protect data in use, no longer requiring users’ trust to the cloud. The emerging service model, Confidential Computing as a Service (CCaaS), is adopted by service providers to offer service similar to the Function-as-a-Serivce manner. However, privacy concerns are raised in CCaaS, especially in multi-user scenarios. CCaaS need to assure the data providers that the service does not leak their privacy to any unauthorized parties and clear their data after the service. To address such privacy concerns with security guarantees, we first formally define the security objective, Proof of Being Forgotten (PoBF), and prove under which security constraints PoBF can be satisfied. Then, these constraints serve as guidelines in the implementation of the PoBF-compliant Framework (PoCF). PoCF consists of a generic library for different hardware TEEs, CCaaS prototype enclaves, and a verifier to prove PoBF-compliance. PoCF leverages Rust’s robust type system and security features, to construct a verified state machine with privacy-preserving contracts. Last, the experiment results show that the protections introduced by PoCF incur minor runtime performance overhead.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Proceeding:
- The DOI is not currently available.
