TLS in the Wild: An Internet-wide Analysis of TLS-based Protocols for Electronic Communication

Holz, Ralph; Amann, Johanna; Mehani, Olivier; Wachs, Matthias; Kâafar, Mohamed Ali

doi:10.14722/ndss.2016.23055

Cited by 58 publications

(35 citation statements)

References 41 publications

(50 reference statements)

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“…For example, Durumeric et al found that the long tail of SMTP servers largely fail to deploy encryption and authentication, leaving users vulnerable to downgrade attacks, which are widespread in the wild [15]. Holz et al also found that email is poorly secured in transit, often due to configuration errors [21]. We study an orthogonal problem.…”

Section: Related Workmentioning

confidence: 99%

I never signed up for this! Privacy implications of email tracking

Englehardt

Han

Narayanan

2018

Proceedings on Privacy Enhancing Technologies

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Abstract:We show that the simple act of viewing emails contains privacy pitfalls for the unwary. We assembled a corpus of commercial mailing-list emails, and find a network of hundreds of third parties that track email recipients via methods such as embedded pixels. About 30% of emails leak the recipient's email address to one or more of these third parties when they are viewed. In the majority of cases, these leaks are intentional on the part of email senders, and further leaks occur if the recipient clicks links in emails. Mail servers and clients may employ a variety of defenses, but we analyze 16 servers and clients and find that they are far from comprehensive. We propose, prototype, and evaluate a new defense, namely stripping tracking tags from emails based on enhanced versions of existing web tracking protection lists.

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Section: Related Workmentioning

confidence: 99%

I never signed up for this! Privacy implications of email tracking

Englehardt

Han

Narayanan

2018

Proceedings on Privacy Enhancing Technologies

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“…3) Cryptographic Assurance with SSL/TLS: We use a final strong filter that is based on our regular Internet-wide scans of SSL/TLS protocols (refer to [23] for further details). For any given hijacking alarm concerning a certain IP prefix, we verify if affected SSL/TLS hosts present the same public key before and during the event.…”

Section: B Filtering Methodologymentioning

confidence: 99%

HEAP: Reliable Assessment of BGP Hijacking Attacks

Schlamp

Holz

Jacquemart

et al. 2016

IEEE J. Select. Areas Commun.

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The detection of BGP prefix hijacking attacks has been the focus of research for more than a decade. However, stateof-the-art techniques fall short of detecting more elaborate types of attack. To study such attacks, we devise a novel formalization of Internet routing, and apply this model to routing anomalies in order to establish a comprehensive attacker model. We use this model to precisely classify attacks and to evaluate their impact and detectability. We analyze the eligibility of attack tactics that suit an attacker's goals and demonstrate that related work mostly focuses on less impactful kinds of attacks.We further propose, implement and test the Hijacking Event Analysis Program (HEAP), a new approach to investigate hijacking alarms. Our approach is designed to seamlessly integrate with previous work in order to reduce the high rates of false alarms inherent to these techniques. We leverage several unique data sources that can reliably disprove malicious intent. First, we make use of an Internet Routing Registry to derive business or organisational relationships between the parties involved in an event. Second, we use a topology-based reasoning algorithm to rule out events caused by legitimate operational practice. Finally, we use Internet-wide network scans to identify SSL/TLS-enabled hosts, which helps to identify non-malicious events by comparing public keys prior to and during an event. In our evaluation, we prove the effectiveness of our approach, and show that day-today routing anomalies are harmless for the most part. More importantly, we use HEAP to assess the validity of publicly reported alarms. We invite researchers to interface with HEAP in order to cross-check and narrow down their hijacking alerts.

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“…Today, 7 years later, we find that same cipher is selected in only 0.001% of connections, and offered by clients in only 8.4% of connections. Later, Holz et al studied the use of TLS in email clients [28]. Lee et al performed active scans of a sample of TLS/SSL servers in order to study ciphers supported and certificates in 2007 [36].…”

Section: A Passive Tls Measurementsmentioning

confidence: 99%

The use of TLS in Censorship Circumvention

Фролов¹,

Wustrow²

2019

Proceedings 2019 Network and Distributed System Security Symposium

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TLS, the Transport Layer Security protocol, has quickly become the most popular protocol on the Internet, already used to load over 70% of web pages in Mozilla Firefox. Due to its ubiquity, TLS is also a popular protocol for censorship circumvention tools, including Tor and Signal, among others. The problem was temporarily corrected by updating to Firefox 45, but only a few months later, meek was blocked again in the same manner, this time by the FortiGuard firewall, which identified a combination of SNI extension values sent by meek and otherwise matching the signature of Firefox 45 [22]. At that time, Firefox 47 had been released, supporting a distinguishable set of features. The rapid pace of new implementations and versions is a difficult task to keep up with. Another motivating example of these challenges is found in the Signal secure messaging application [57]. Until recently, Signal employed domain fronting to evade censorship in several countries including Egypt, Saudi Arabia, and the United Arab Emirates [25], [41]. However, due to a complicated interaction with the library it used to implement TLS, we find that Client Hello messages sent by Signal while domain fronting differ from their intended specification, ultimately allowing them to be distinguished from the implementations

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TLS in the Wild: An Internet-wide Analysis of TLS-based Protocols for Electronic Communication

Cited by 58 publications

References 41 publications

I never signed up for this! Privacy implications of email tracking

I never signed up for this! Privacy implications of email tracking

HEAP: Reliable Assessment of BGP Hijacking Attacks

The use of TLS in Censorship Circumvention

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