Andrew Martin

Eman Salem Alashwali, Pawel Szalachowski, Andrew Martin

If two or more identical HTTPS clients, located at different geographic locations (regions), make an HTTPS request to the same domain (e.g. example.com), on the same day, will they receive the same HTTPS security guarantees in response? Our results give evidence that this is not always the case. We conduct scans for the top 250,000 most visited domains on the Internet, from clients located at five different regions: Australia, Brazil, India, the UK, and the US. Our scans gather data from both application (URLs and HTTP headers) and transport (servers' selected TLS version, ciphersuite, and certificate) layers. Overall, we find that HTTPS inconsistencies at the application layer are higher than those at the transport layer. We also find that HTTPS security inconsistencies are strongly related to URLs and IPs diversity among regions, and to a lesser extent to the presence of redirections. Further manual inspection shows that there are several reasons behind URLs diversity among regions such as downgrading to the plain-HTTP protocol, using different subdomains, different TLDs, or different home page documents. Furthermore, we find that downgrading to plain-HTTP is related to websites' regional blocking. We also provide attack scenarios that show how an attacker can benefit from HTTPS security inconsistencies, and introduce a new attack scenario which we call the "region confusion" attack. Finally, based on our analysis and observations, we provide discussion, which include some recommendations such as the need for testing tools for domain administrators and users that help to mitigate and detect regional domains' inconsistencies, standardising regional domains format with the same-origin policy (of domains) in mind, standardising secure URL redirections, and avoid redirections whenever possible.

Eman Salem Alashwali, Pawel Szalachowski, Andrew Martin

Forward Secrecy (FS) is a security property in key-exchange algorithms which guarantees that a compromise in the secrecy of a long-term private-key does not compromise the secrecy of past session keys. With a growing awareness of long-term mass surveillance programs by governments and others, FS has become widely regarded as a highly desirable property. This is particularly true in the TLS protocol, which is used to secure Internet communication. In this paper, we investigate FS in pre-TLS 1.3 protocols, which do not mandate FS, but still widely used today. We conduct an empirical analysis of over 10 million TLS servers from three different datasets using a novel heuristic approach. Using a modern TLS client handshake algorithms, our results show 5.37% of top domains, 7.51% of random domains, and 26.16% of random IPs do not select FS key-exchange algorithms. Surprisingly, 39.20% of the top domains, 24.40% of the random domains, and 14.46% of the random IPs that do not select FS, do support FS. In light of this analysis, we discuss possible paths toward forward secure Internet traffic. As an improvement of the current state, we propose a new client-side mechanism that we call "Best Effort Forward Secrecy" (BEFS), and an extension of it that we call "Best Effort Forward Secrecy and Authenticated Encryption" (BESAFE), which aims to guide (force) misconfigured servers to FS using a best effort approach. Finally, within our analysis, we introduce a novel adversarial model that we call "discriminatory" adversary, which is applicable to the TLS protocol.

Eman Salem Alashwali, Pawel Szalachowski, Andrew Martin

Experience shows that most researchers and developers tend to treat plain-domains (those that are not prefixed with "www" sub-domains, e.g. "example.com") as synonyms for their equivalent www-domains (those that are prefixed with "www" sub-domains, e.g. "www.example.com"). In this paper, we analyse datasets of nearly two million plain-domains against their equivalent www-domains to answer the following question: Do plain-domains and their equivalent www-domains differ in TLS security configurations and certificates? If so, to what extent? Our results provide evidence of an interesting phenomenon: plain-domains and their equivalent www-domains differ in TLS security configurations and certificates in a non-trivial number of cases. Furthermore, www-domains tend to have stronger security configurations than their equivalent plain-domains. Interestingly, this phenomenon is more prevalent in the most-visited domains than in randomly-chosen domains. Further analysis of the top domains dataset shows that 53.35% of the plain-domains that show one or more weakness indicators (e.g. expired certificate) that are not shown in their equivalent www-domains perform HTTPS redirection from HTTPS plain-domains to their equivalent HTTPS www-domains. Additionally, 24.71% of these redirections contains plain-text HTTP intermediate URLs. In these cases, users see the final www-domains with strong TLS configurations and certificates, but in fact, the HTTPS request has passed through plain-domains that have less secure TLS configurations and certificates. Clearly, such a set-up introduces a weak link in the security of the overall interaction.

Adriana Guevara-Rukoz, Alejandrina Cristia, Bogdan Ludusan et al.

We investigate whether infant-directed speech (IDS) could facilitate word form learning when compared to adult-directed speech (ADS). To study this, we examine the distribution of word forms at two levels, acoustic and phonological, using a large database of spontaneous speech in Japanese. At the acoustic level we show that, as has been documented before for phonemes, the realizations of words are more variable and less discriminable in IDS than in ADS. At the phonological level, we find an effect in the opposite direction: the IDS lexicon contains more distinctive words (such as onomatopoeias) than the ADS counterpart. Combining the acoustic and phonological metrics together in a global discriminability score reveals that the bigger separation of lexical categories in the phonological space does not compensate for the opposite effect observed at the acoustic level. As a result, IDS word forms are still globally less discriminable than ADS word forms, even though the effect is numerically small. We discuss the implication of these findings for the view that the functional role of IDS is to improve language learnability.

Ahmad Atamli-Reineh, Andrew Martin

Application size and complexity are the underlying cause of numerous security vulnerabilities in code. In order to mitigate the risks arising from such vulnerabilities, various techniques have been proposed to isolate the execution of sensitive code from the rest of the application and from other software on the platform (e.g. the operating system). However, even with these partitioning techniques, it is not immediately clear exactly how they can and should be used to partition applications. What overall partitioning scheme should be followed; what granularity of the partitions should be. To some extent, this is dependent on the capabilities and performance of the partitioning technology in use. For this work, we focus on the upcoming Intel Software Guard Extensions (SGX) technology as the state-of-the-art in this field. SGX provides a trusted execution environment, called an enclave, that protects the integrity of the code and the confidentiality of the data inside it from other software, including the operating system. We present a novel framework consisting of four possible schemes under which an application can be partitioned. These schemes range from coarse-grained partitioning, in which the full application is included in a single enclave, through ultra-fine partitioning, in which each application secret is protected in an individual enclave. We explain the specific security benefits provided by each of the partitioning schemes and discuss how the performance of the application would be affected. To compare the different partitioning schemes, we have partitioned OpenSSL using four different schemes. We discuss SGX properties together with the implications of our design choices in this paper.

Ahmad-Atamli Reineh, Giuseppe Petracca, Janne Uusilehto et al.

The emergence of mobile applications to execute sensitive operations has brought a myriad of security threats to both enterprises and users. In order to benefit from the large potential in smartphones there is a need to manage the risks arising from threats, while maintaining an easy interface for the users. In this paper we investigate the use of Trusted Platform Model (TPM) 2.0 to develop a secure application for smartphones using Windows Phone 8.1. In particular, we suggest a framework based on remote attestation as a proxy to authenticate remote services, where the device is associated to the user and replaces the users credentials. In addition, we use the TPM 2.0 to enable secured information and data storage within the device itself. We present an implementation and performance evaluation of the suggested architecture that uses our novel attestation and authentication scheme and reveal the caveats of using software TPM in todays mobile devices.

Nalin Asanka Gamagedara Arachchilage, Cornelius Namiluko, Andrew Martin

In any given collaboration, information needs to flow from one participant to another. While participants may be interested in sharing information with one another, it is often necessary for them to establish the impact of sharing certain kinds of information. This is because certain information could have detrimental effects when it ends up in wrong hands. For this reason, any would-be participant in a collaboration may need to establish the guarantees that the collaboration provides, in terms of protecting sensitive information, before joining the collaboration as well as evaluating the impact of sharing a given piece of information with a given set of entities. The concept of a trust domains aims at managing trust-related issues in information sharing. It is essential for enabling efficient collaborations. Therefore, this research attempts to develop a taxonomy for trust domains with measurable trust characteristics, which provides security-enhanced, distributed containers for the next generation of composite electronic services for supporting collaboration and data exchange within and across multiple organisations. Then the developed taxonomy is applied to possible scenarios (e.g. Health Care Service Scenario and ConfiChair Scenario), in which the concept of trust domains could be useful.

Nalin Asanka Gamagedara Arachchilage, Andrew Martin

Information sharing has become a vital part in our day-to-day life due to the pervasiveness of Internet technology. In any given collaboration, information needs to flow from one participant to another. While participants may be interested in sharing information with one another, it is often necessary for them to establish the impact of sharing certain kinds of information. This is because certain information could have detrimental effects when it ends up in wrong hands. For this reason, any would-be participant in a given collaboration may need to establish the guarantees that the collaboration provides, in terms of protecting sensitive information, before joining the collaboration as well as evaluating the impact of sharing a given piece of information with a given set of entities. In order to address this issue, earlier work introduced a trust domains taxonomy that aims at managing trust-related issues in information sharing. This paper attempts to empirically investigate the proposed taxonomy through a possible scenario (e.g. the ConfiChair system). The study results determined that Role, Policy, Action, Control, Evidence and Asset elements should be incorporated into the taxonomy for securely sharing information among others. Additionally, the study results showed that the ConfiChair, a novel cloud-based conference management system, offers strong privacy and confidentiality guarantees.