4,050 research outputs found
Denial-of-Service Resistance in Key Establishment
Denial of Service (DoS) attacks are an increasing problem for network connected systems. Key establishment protocols are applications that are particularly vulnerable to DoS attack as they are typically required to perform computationally expensive cryptographic operations in order to authenticate the protocol initiator and to generate the cryptographic keying material that will subsequently be used to secure the communications between initiator and responder. The goal of DoS resistance in key establishment protocols is to ensure that attackers cannot prevent a legitimate initiator and responder deriving cryptographic keys without expending resources beyond a responder-determined threshold. In this work we review the strategies and techniques used to improve resistance to DoS attacks. Three key establishment protocols implementing DoS resistance techniques are critically reviewed and the impact of misapplication of the techniques on DoS resistance is discussed. Recommendations on effectively applying resistance techniques to key establishment protocols are made
Tracking Users across the Web via TLS Session Resumption
User tracking on the Internet can come in various forms, e.g., via cookies or
by fingerprinting web browsers. A technique that got less attention so far is
user tracking based on TLS and specifically based on the TLS session resumption
mechanism. To the best of our knowledge, we are the first that investigate the
applicability of TLS session resumption for user tracking. For that, we
evaluated the configuration of 48 popular browsers and one million of the most
popular websites. Moreover, we present a so-called prolongation attack, which
allows extending the tracking period beyond the lifetime of the session
resumption mechanism. To show that under the observed browser configurations
tracking via TLS session resumptions is feasible, we also looked into DNS data
to understand the longest consecutive tracking period for a user by a
particular website. Our results indicate that with the standard setting of the
session resumption lifetime in many current browsers, the average user can be
tracked for up to eight days. With a session resumption lifetime of seven days,
as recommended upper limit in the draft for TLS version 1.3, 65% of all users
in our dataset can be tracked permanently.Comment: 11 page
Performance analysis of next generation web access via satellite
Acknowledgements This work was partially funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No. 644334 (NEAT). The views expressed are solely those of the author(s).Peer reviewedPostprin
Postcards from the post-HTTP world: Amplification of HTTPS vulnerabilities in the web ecosystem
HTTPS aims at securing communication over the Web by providing a cryptographic protection layer that ensures the confidentiality and integrity of communication and enables client/server authentication. However, HTTPS is based on the SSL/TLS protocol suites that have been shown to be vulnerable to various attacks in the years. This has required fixes and mitigations both in the servers and in the browsers, producing a complicated mixture of protocol versions and implementations in the wild, which makes it unclear which attacks are still effective on the modern Web and what is their import on web application security. In this paper, we present the first systematic quantitative evaluation of web application insecurity due to cryptographic vulnerabilities. We specify attack conditions against TLS using attack trees and we crawl the Alexa Top 10k to assess the import of these issues on page integrity, authentication credentials and web tracking. Our results show that the security of a consistent number of websites is severely harmed by cryptographic weaknesses that, in many cases, are due to external or related-domain hosts. This empirically, yet systematically demonstrates how a relatively limited number of exploitable HTTPS vulnerabilities are amplified by the complexity of the web ecosystem
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