3 research outputs found
Evaluating practical QUIC website fingerprinting defenses for the masses
Abstract: Website fingerprinting (WF) is a well-known threat to users' web privacy. New Internet standards, such as QUIC, include padding to support defenses against WF. Previous work on QUIC WF only analyzes the effectiveness of defenses when users are behind a VPN. Yet, this is not how most users browse the Internet. In this paper, we provide a comprehensive evaluation of QUIC-padding-based defenses against WF when users directly browse the web, i.e., without VPNs, HTTPS proxies, or other tunneling protocols. We confirm previous claims that network-layer padding cannot provide effective protection against powerful adversaries capable of observing all traffic traces. We show that the claims hold even against adversaries with constraints on traffic visibility and processing power. We then show that the current approach to web development, in which the use of third-party resources is the norm, impedes the effective use of padding-based defenses as it requires first and third parties to coordinate in order to thwart traffic analysis. We show that even when coordination is possible, in most cases, protection comes at a high cost.Peer reviewe
Assessing the Privacy Benefits of Domain Name Encryption
As Internet users have become more savvy about the potential for their
Internet communication to be observed, the use of network traffic encryption
technologies (e.g., HTTPS/TLS) is on the rise. However, even when encryption is
enabled, users leak information about the domains they visit via DNS queries
and via the Server Name Indication (SNI) extension of TLS. Two recent proposals
to ameliorate this issue are DNS over HTTPS/TLS (DoH/DoT) and Encrypted SNI
(ESNI). In this paper we aim to assess the privacy benefits of these proposals
by considering the relationship between hostnames and IP addresses, the latter
of which are still exposed. We perform DNS queries from nine vantage points
around the globe to characterize this relationship. We quantify the privacy
gain offered by ESNI for different hosting and CDN providers using two
different metrics, the k-anonymity degree due to co-hosting and the dynamics of
IP address changes. We find that 20% of the domains studied will not gain any
privacy benefit since they have a one-to-one mapping between their hostname and
IP address. On the other hand, 30% will gain a significant privacy benefit with
a k value greater than 100, since these domains are co-hosted with more than
100 other domains. Domains whose visitors' privacy will meaningfully improve
are far less popular, while for popular domains the benefit is not significant.
Analyzing the dynamics of IP addresses of long-lived domains, we find that only
7.7% of them change their hosting IP addresses on a daily basis. We conclude by
discussing potential approaches for website owners and hosting/CDN providers
for maximizing the privacy benefits of ESNI.Comment: In Proceedings of the 15th ACM Asia Conference on Computer and
Communications Security (ASIA CCS '20), October 5-9, 2020, Taipei, Taiwa