Studying TLS Usage in Android Apps

In-network middleboxes are vital for the Internet-of-Things (IoT) system security, but the widely adopted transport layer security (TLS) protocol blinds application-level middleboxes due to the encryption of traffic data. To resolve this problem, many solutions have been proposed to date. Among them, SplitTLS is widely adopted in the industry by proxy manufacturers. It requires TLS client to install customized root certificates and incurs additional security flaws, e.g., disabling server authentication and using weak cipher suites. Another approach is to customize the TLS protocol where middleboxes are enabled via either performing handshake directly with TLS endpoints or receiving session key materials in an out-of-band manner. Overall, current solutions would either jeopardize the original TLS handshake procedure or incur additional overheads on the endpoints. In this article, we design a new middlebox-enhanced TLS (ME-TLS), which enables endpoints to introduce authenticated middleboxes into a TLS session while control middleboxes' access permission and processing order of traffic data. Particularly, in our proposed ME-TLS, the handshake structure of TLS keeps unchanged and middleboxes work in a passive manner. That is, middleboxes in the ME-TLS could recover session key materials by monitoring handshake messages passively instead of interacting with endpoints; secondary secure channels for key transmission are also not needed in our ME-TLS. We implement our ME-TLS based on the TLS 1.3 protocol and evaluate its performances. The experimental results demonstrate that our proposal is practical and deployable for real-world IoT scenarios.

To provide secure content delivery, Transport Layer Security (TLS) has become a de facto standard over a couple of decades. However, TLS has a long history of security weaknesses and drawbacks. Thus, the security of TLS has been enhanced by addressing security problems through continuous version upgrades. Meanwhile, to provide fast content delivery globally, websites (or origin web servers) need to deploy and administer many machines in globally distributed environments. They often delegate the management of machines to web hosting services or content delivery networks (CDNs), where the security configurations of distributed servers may vary spatially depending on the managing entities or locations. Based on these spatial differences in TLS security, we find that the security level of TLS connections (and their web services) can be lowered. After collecting the information of (web) domains that exhibit different TLS versions and cryptographic options depending on clients' locations, we show that it is possible to redirect TLS handshake messages to weak TLS servers, which both the origin server and the client may not be aware of. We investigate 7M domains with these spatial differences of security levels in the wild and conduct the analyses to better understand the root causes of this phenomenon. We also measure redirection delays at various locations in the world to see whether there are noticeable delays in redirections.

Mobile applications are granted access to large amounts of data both stored and sensed on a user’s device. While the data stored on these devices can be protected with encryption, where the private keys are protected through a combination of biometric authentication and passcodes, it is important to consider the security of data in transit and the many connections applications make to different domains. Often, these domains are unknown to the user where they can include third-party domains and tracking services. In this paper, we investigate the current state of transport layer security (TLS) utilization across the top information sharing applications in the iOS App Store. Through this study, we are able to better understand which domains follow best practices and use recommended ciphers and TLS versions. We also provide deeper insight into the prominent use of tracking services and how they differ in their utilization of TLS. Our study utilizes a proxy service to detect the domains that applications communicate with and then uses OpenSSL to analyze the supported ciphers, TLS versions, and certificate details. We also leverage domain analysis from DuckDuckGo Tracker Radar to differentiate tracking domains. From this study, we analyzed 965 unique domains and found that 935 (96%) use a cipher that is not recommended and only 23 (2%) of the domains strictly followed recommendations on cipher and TLS utilization. While most domains are utilizing recommended versions of TLS and recommended ciphers, this study shows there are many that still support vulnerable versions of TLS and vulnerable ciphers, leaving the user’s data at risk.

Chapter 59 - Virtual Private Networks

SSL/TLS (Secure Socket Layer/Transport Layer Security) has been used as a de facto security protocol to protect users' sensitive information in Android apps, which often need to communicate with servers online to provide users with some of their functionalities and services. Since most Android users tend to be either unaware of or unable to understand the security protocol well, it is critically important to investigate if SSL/TLS is used properly and implemented correctly to protect users' sensitive information such as credentials. In this paper, we seek to shine some light into this important issue by studying the usage of the security protocol in 200 most popular Android apps downloaded from Google Play. We found out that only 4% of these apps are vulnerable to two well-known attacks against the protocol, and this shows huge improvement of SSL/TLS usage in Android apps when compared to the results from a study conducted in 2012, where 100% of Android apps under the study were vulnerable.

As more and more sensitive data is transferred from mobile applications across unsecured channels, it seems imperative that transport layer encryption should be used in any non-trivial instance. Yet, research indicates that many Android developers do not use HTTPS or violate rules which protect user data from man-in-the-middle attacks. This paper seeks to find a root cause of the disparities between theoretical HTTPS usage and in-the-wild implementation of the protocol by looking into Android applications, online resources, and papers published by HTTPS and Android security researchers. From these resources, we extract a set of barrier categories that exist in the path of proper TLS use. These barriers not only include improper developer practices, but also server misconfiguration, lacking documentation, flaws in libraries, the fundamentally complex TLS PKI system, and a lack of consumer understanding of the importance of HTTPS. Following this discussion, we compile a set of potential solutions and patches to better secure Android HTTPS and the TLS/SSL protocol in general. We conclude our survey with gaps in current understanding of the environment and suggestions for further research.

This review chapter provides an in-depth exploration of various aspects of data security, ranging from foundational principles to advanced techniques. It sheds light on the importance of maintaining confidentiality, integrity, and availability of data and presents a comprehensive overview of technologies and methodologies that can be employed to achieve robust data security. In today's digital age, ensuring the security and protection of data has become paramount. This research chapter explores various topics related to data security, including confidentiality, integrity, and availability. It also delves into the role of blockchain technology, zero-trust architecture, secure coding practices, legal and ethical considerations, homomorphic encryption, secure multi-party computation, hash functions and digital signatures, secure communication protocols, cryptocurrency and blockchain security, as well as cryptanalysis and side-channel attacks.It highlights various techniques and technologies that can be employed to protect data confidentiality, including encryption and access control mechanisms. Blockchain technology has emerged as a groundbreaking solution for enhancing data security. Zero-trust architecture challenges traditional security models by adopting a holistic and dynamic approach to data protection. Secure coding practices and DevSecOps play a vital role in developing secure software applications. The chapter investigates the importance of integrating security measures throughout the software development lifecycle. It emphasizes the adoption of secure coding practices and the implementation of DevSecOps methodologies to build resilient and secure software systems. Legal and ethical considerations are crucial when addressing data security. Homomorphic encryption and secure multi-party computation are advanced cryptographic techniques that allow data to be processed securely while encrypted. The chapter examines the principles and applications of these techniques, highlighting their significance in scenarios where privacy is paramount. Hash functions and digital signatures form the backbone of data authentication and integrity. The chapter discusses the properties and applications of hash functions and digital signatures in verifying the integrity and authenticity of data. Secure communication protocols are essential for protecting data during transmission. The chapter explores various secure communication protocols, such as Transport Layer Security (TLS), and examines their role in ensuring data confidentiality, integrity, and authenticity. Cryptocurrency and blockchain security focus on the secure storage and transfer of digital assets. The research chapter investigates the security considerations specific to cryptocurrencies and explores how block chain technology can mitigate vulnerabilities and ensure the trustworthiness of transactions. Cryptanalysis and side-channel attacks are threats to cryptographic systems. The chapter discusses these attack techniques, highlighting their potential risks and the measures that can be taken to counter them.

Near Field Communication (NFC) is used for a wide range of security-critical applications such as payment or access control. Although such applications require secured data transfer, the NFC protocol does not include transport layer security. Other protocols that are built on top of NFC, such as the NFC data exchange format (NDEF), only provide insufficient security measures. Therefore, implemented security solutions are often application specific and do not follow well-established standards. To facilitate NFC usage in the Internet of Things (IoT) where millions of devices need to be secured, an efficient and sufficiently secured NFC-based protocol needs to be developed. In this paper, we present the Quick and Secured NFC (QSNFC) protocol. Our protocol is capable of performing more efficient key agreements for recurring connections, and thus, can be used as an efficient alternative to the Transport Layer Security (TLS) protocol.

The relevance of the study was determined by the growing volume of unstructured data in the mobile environment, which required a rethinking of classical approaches to the protection in conditions of limited resources and dynamic use. The purpose of the study was to conduct a comprehensive analysis of methods for protecting unstructured information in the mobile environment and to identify key barriers to the effective implementation. The methodology was based on a theoretical and analytical approach, which included the systematisation of protection methods, a comparative analysis of cryptographic algorithms, an assessment of authentication and access control models, as well as an analysis of cloud security mechanisms. It was established that symmetric encryption Advanced Encryption Standard in Cipher Block Chaining mode provided effective local protection but required careful management of initialisation vectors. It was found that Elliptic Curve Cryptography outperformed Rivest-Shamir-Adleman in terms of energy efficiency and performance, and BLAKE3 outperformed Secure Hash Algorithm 256 in terms of speed, energy consumption, and parallelism support. It was generalised that access control models were insufficiently adapted to the dynamics of the mobile environment, and the most effective were context-oriented and multifactor approaches, in particular with the use of biometric and behavioural authentication. It was found that a combination of client-side encryption, identity management, and cloud backup ensured the highest level of protection with proper implementation. It was established that the effectiveness of HyperText Transfer Protocol Secure, Transport Layer Security 1.3, and Virtual Private Network protocols depended on the type of data and interaction scenario, and the use required a balance between security, performance, and the context of use. Eight key challenges were identified, the relevance of which to mobile security practice was confirmed through comparison with the OWASP Mobile Top 10 categories: data leakage, limited resources, complexity of authentication, dynamic access control, use of public networks, platform fragmentation, application opacity, and legal barriers. It was determined that the effectiveness of protection methods was conditioned by the context of application – the type of data, device architecture, interaction scenario, and available infrastructure – which required an adaptive choice of solutions. The results obtained confirmed that traditional approaches to information security required adaptation to the specifics of mobile platforms. The study has practical value for security solution developers, corporate system administrators, and policymakers in the field of cybersecurity

Dynamic privacy leakage analysis of Android third-party libraries

Privacy protection in computer communication is gaining attention because plaintext transmission without encryption can be eavesdropped on and intercepted. Accordingly, the use of encrypted communication protocols is on the rise, along with the number of cyberattacks exploiting them. Decryption is essential for preventing attacks, but it risks privacy infringement and incurs additional costs. Network fingerprinting techniques are among the best alternatives, but existing techniques are based on information from the TCP/IP stack. They are expected to be less effective because cloud-based and software-defined networks have ambiguous boundaries, and network configurations not dependent on existing IP address schemes increase. Herein, we investigate and analyze the Transport Layer Security (TLS) fingerprinting technique, a technology that can analyze and classify encrypted traffic without decryption while addressing the problems of existing network fingerprinting techniques. Background knowledge and analysis information for each TLS fingerprinting technique is presented herein. We discuss the pros and cons of two groups of techniques, fingerprint collection and artificial intelligence (AI)-based. Regarding fingerprint collection techniques, separate discussions on handshake messages ClientHello/ServerHello, statistics of handshake state transitions, and client responses are provided. For AI-based techniques, discussions on statistical, time series, and graph techniques according to feature engineering are presented. In addition, we discuss hybrid and miscellaneous techniques that combine fingerprint collection with AI techniques. Based on these discussions, we identify the need for a step-by-step analysis and control study of cryptographic traffic to effectively use each technique and present a blueprint.

Third-party libraries (TPLs) as essential parts in the mobile ecosystem have become one of the most significant contributors to the huge success of Android, which facilitate the fast development of Android applications. Detecting TPLs in Android apps is also important for downstream tasks, such as malware and repackaged apps identification. To identify in-app TPLs, we need to solve several challenges, such as TPL dependency, code obfuscation, precise version representation. Unfortunately, existing TPL detection tools have been proved that they have not solved these challenges very well, let alone specify the exact TPL versions. To this end, we propose a system, named ATVHunter, which can pinpoint the precise vulnerable in-app TPL versions and provide detailed information about the vulnerabilities and TPLs. We propose a two-phase detection approach to identify specific TPL versions. Specifically, we extract the Control Flow Graphs as the coarse-grained feature to match potential TPLs in the predefined TPL database, and then extract opcode in each basic block of CFG as the fine-grained feature to identify the exact TPL versions. We build a comprehensive TPL database (189,545 unique TPLs with 3,006,676 versions) as the reference database. Meanwhile, to identify the vulnerable in-app TPL versions, we also construct a comprehensive and known vulnerable TPL database containing 1,180 CVEs and 224 security bugs. Experimental results show ATVHunter outperforms state-of-the-art TPL detection tools, achieving 90.55% precision and 88.79% recall with high efficiency, and is also resilient to widely-used obfuscation techniques and scalable for large-scale TPL detection. Furthermore, to investigate the ecosystem of the vulnerable TPLs used by apps, we exploit ATVHunter to conduct a large-scale analysis on 104,446 apps and find that 9,050 apps include vulnerable TPL versions with 53,337 vulnerabilities and 7,480 security bugs, most of which are with high risks and are not recognized by app developers.

TLS protocol is an essential part of secure Internet communication. In past, many attacks have been identified on the protocol. Most of these attacks are due to flaws in protocol implementation. The flaws are due to improper design and implementation of program logic by programmers. One of the widely used implementation of TLS is SChannel which is used in Windows operating system since its inception. We have used protocol state fuzzing to identify vulnerable and undesired state transitions in the state machine of the protocol for various versions of SChannel. The client as well as server components have been analyzed thoroughly using this technique and various flaws have been discovered in the implementation. Exploitation of these flaws under specific circumstances may lead to serious attacks which could disrupt secure communication. In this paper, we analyze state machine models of TLS protocol implementation of SChannel library and describe weaknesses and design flaws in these models, found using protocol state fuzzing.

Abstract. Methods for the determination of ship fuel sulphur content and NOx emission factors based on remote measurements have been compared in the harbour of Rotterdam and compared to direct stack emission measurements on the ferry Stena Hollandica. The methods were selected based on a review of the available literature on ship emission measurements. They were either optical (LIDAR, Differential Optical Absorption Spectroscopy (DOAS), UV camera), combined with model-based estimates of fuel consumption, or based on the so called "sniffer" principle, where SO2 or NOx emission factors are determined from simultaneous measurement of the increase of CO2 and SO2 or NOx concentrations in the plume of the ship compared to the background. The measurements were performed from stations at land, from a boat and from a helicopter. Mobile measurement platforms were found to have important advantages compared to the land-based ones because they allow optimizing the sampling conditions and sampling from ships on the open sea. Although optical methods can provide reliable results it was found that at the state of the art level, the "sniffer" approach is the most convenient technique for determining both SO2 and NOx emission factors remotely. The average random error on the determination of SO2 emission factors comparing two identical instrumental set-ups was 6%. However, it was found that apparently minor differences in the instrumental characteristics, such as response time, could cause significant differences between the emission factors determined. Direct stack measurements showed that about 14% of the fuel sulphur content was not emitted as SO2. This was supported by the remote measurements and is in agreement with the results of other field studies.

Smart devices with easy Internet accessibility, mobility and usability are changing various service environment such as mobile office, smart work, mobile finance, e-government and so on. Meanwhile, these smart device has widened into military area in an effort to enhance mission command and situational awareness. This paper describes functional considerations in military-grade mobile security platform based on a mobile hypervisor. The military-grade mobile platform will be provided more security enhancement than current mobile services. We suggest four features for enhancing a mobile platform including domain separation, secure file management, secure middleware and access control.