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2019-11-04
Abani, Noor, Braun, Torsten, Gerla, Mario.  2018.  Betweenness Centrality and Cache Privacy in Information-Centric Networks. Proceedings of the 5th ACM Conference on Information-Centric Networking. :106-116.

In-network caching is a feature shared by all proposed Information Centric Networking (ICN) architectures as it is critical to achieving a more efficient retrieval of content. However, the default "cache everything everywhere" universal caching scheme has caused the emergence of several privacy threats. Timing attacks are one such privacy breach where attackers can probe caches and use timing analysis of data retrievals to identify if content was retrieved from the data source or from the cache, the latter case inferring that this content was requested recently. We have previously proposed a betweenness centrality based caching strategy to mitigate such attacks by increasing user anonymity. We demonstrated its efficacy in a transit-stub topology. In this paper, we further investigate the effect of betweenness centrality based caching on cache privacy and user anonymity in more general synthetic and real world Internet topologies. It was also shown that an attacker with access to multiple compromised routers can locate and track a mobile user by carrying out multiple timing analysis attacks from various parts of the network. We extend our privacy evaluation to a scenario with mobile users and show that a betweenness centrality based caching policy provides a mobile user with path privacy by increasing an attacker's difficulty in locating a moving user or identifying his/her route.

Kahani, Nafiseh, Fallah, Mehran S..  2018.  A Reactive Defense Against Bandwidth Attacks Using Learning Automata. Proceedings of the 13th International Conference on Availability, Reliability and Security. :31:1-31:6.

This paper proposes a new adaptively distributed packet filtering mechanism to mitigate the DDoS attacks targeted at the victim's bandwidth. The mechanism employs IP traceback as a means of distinguishing attacks from legitimate traffic, and continuous action reinforcement learning automata, with an improved learning function, to compute effective filtering probabilities at filtering routers. The solution is evaluated through a number of experiments based on actual Internet data. The results show that the proposed solution achieves a high throughput of surviving legitimate traffic as a result of its high convergence speed, and can save the victim's bandwidth even in case of varying and intense attacks.

Serror, Martin, Henze, Martin, Hack, Sacha, Schuba, Marko, Wehrle, Klaus.  2018.  Towards In-Network Security for Smart Homes. Proceedings of the 13th International Conference on Availability, Reliability and Security. :18:1-18:8.

The proliferation of the Internet of Things (IoT) in the context of smart homes entails new security risks threatening the privacy and safety of end users. In this paper, we explore the design space of in-network security for smart home networks, which automatically complements existing security mechanisms with a rule-based approach, i. e., every IoT device provides a specification of the required communication to fulfill the desired services. In our approach, the home router as the central network component then enforces these communication rules with traffic filtering and anomaly detection to dynamically react to threats. We show that in-network security can be easily integrated into smart home networks based on existing approaches and thus provides additional protection for heterogeneous IoT devices and protocols. Furthermore, in-network security relieves users of difficult home network configurations, since it automatically adapts to the connected devices and services.

Daoud, Luka, Rafla, Nader.  2018.  Routing Aware and Runtime Detection for Infected Network-on-Chip Routers. 2018 IEEE 61st International Midwest Symposium on Circuits and Systems (MWSCAS). :775-778.

Network-on-Chip (NoC) architecture is the communication heart of the processing cores in Multiprocessors System-on-Chip (MPSoC), where messages are routed from a source to a destination through intermediate nodes. Therefore, NoC has become a target to security attacks. By experiencing outsourcing design, NoC can be infected with a malicious Hardware Trojans (HTs) which potentially degrade the system performance or leave a backdoor for secret key leaking. In this paper, we propose a HT model that applies a denial of service attack by misrouting the packets, which causes deadlock and consequently degrading the NoC performance. We present a secure routing algorithm that provides a runtime HT detection and avoiding scheme. Results show that our proposed model has negligible overhead in area and power, 0.4% and 0.6%, respectively.

Vegda, Hiral, Modi, Nimesh.  2018.  Secure and Efficient Approach to Prevent Ad Hoc Network Attacks Using Intrusion Detection System. 2018 Second International Conference on Intelligent Computing and Control Systems (ICICCS). :129-133.

In Ad hoc networks the main purpose is communication without infrastructure and there are many implementations already done on that. There is little effort done for security to prevent threats in ad hoc networks (like MANETs). It is already proven that; there is no any centralized mechanism for defence against threats, such as a firewall, an intrusion detection system, or a proxy in ad hoc networks. Ad hoc networks are very convenient due to its features like self-maintenance, self-organizing and providing wireless communication. In Ad hoc networks there is no fixed infrastructure in which every node works like simply a router which stores and forwards packet to final destination. Due to these dynamic topology features, Ad hoc networks are anywhere, anytime. Therefore, it is necessary to make a secure mechanism for the ad hoc components so that with flexibility they have that security also. This paper shows the secure and flexible implementation about to protect any ad hoc networks. This proposed system design is perfect solution to provide security with flexibility by providing a hybrid system which combines ECC and MAES to detect and prevent Ad hoc network attacks using Intrusion detection system. The complete proposed system designed on NS 2.35 software using Ubuntu (Linux) OS.

Altay, Osman, Ulas, Mustafa.  2018.  Location Determination by Processing Signal Strength of Wi-Fi Routers in the Indoor Environment with Linear Discriminant Classifier. 2018 6th International Symposium on Digital Forensic and Security (ISDFS). :1-4.

Location determination in the indoor areas as well as in open areas is important for many applications. But location determination in the indoor areas is a very difficult process compared to open areas. The Global Positioning System (GPS) signals used for position detection is not effective in the indoor areas. Wi-Fi signals are a widely used method for localization detection in the indoor area. In the indoor areas, localization can be used for many different purposes, such as intelligent home systems, locations of people, locations of products in the depot. In this study, it was tried to determine localization for with the classification method for 4 different areas by using Wi-Fi signal values obtained from different routers for indoor location determination. Linear discriminant analysis (LDA) classification was used for classification. In the test using 10k fold cross-validation, 97.2% accuracy value was calculated.

Li, Teng, Ma, Jianfeng, Pei, Qingqi, Shen, Yulong, Sun, Cong.  2018.  Anomalies Detection of Routers Based on Multiple Information Learning. 2018 International Conference on Networking and Network Applications (NaNA). :206-211.

Routers are important devices in the networks that carry the burden of transmitting information among the communication devices on the Internet. If a malicious adversary wants to intercept the information or paralyze the network, it can directly attack the routers and then achieve the suspicious goals. Thus, preventing router security is of great importance. However, router systems are notoriously difficult to understand or diagnose for their inaccessibility and heterogeneity. The common way of gaining access to the router system and detecting the anomaly behaviors is to inspect the router syslogs or monitor the packets of information flowing to the routers. These approaches just diagnose the routers from one aspect but do not consider them from multiple views. In this paper, we propose an approach to detect the anomalies and faults of the routers with multiple information learning. We try to use the routers' information not from the developer's view but from the user' s view, which does not need any expert knowledge. First, we do the offline learning to transform the benign or corrupted user actions into the syslogs. Then, we try to decide whether the input routers' conditions are poor or not with clustering. During the detection phase, we use the distance between the event and the cluster to decide if it is the anomaly event and we can provide the corresponding solutions. We have applied our approach in a university network which contains Cisco, Huawei and Dlink routers for three months. We aligned our experiment with former work as a baseline for comparison. Our approach can gain 89.6% accuracy in detecting the attacks which is 5.1% higher than the former work. The results show that our approach performs in limited time as well as memory usages and has high detection and low false positives.

Harrison, William L., Allwein, Gerard.  2018.  Semantics-Directed Prototyping of Hardware Runtime Monitors. 2018 International Symposium on Rapid System Prototyping (RSP). :42-48.

Building memory protection mechanisms into embedded hardware is attractive because it has the potential to neutralize a host of software-based attacks with relatively small performance overhead. A hardware monitor, being at the lowest level of the system stack, is more difficult to bypass than a software monitor and hardware-based protections are also potentially more fine-grained than is possible in software: an individual instruction executing on a processor may entail multiple memory accesses, all of which may be tracked in hardware. Finally, hardware-based protection can be performed without the necessity of altering application binaries. This article presents a proof-of-concept codesign of a small embedded processor with a hardware monitor protecting against ROP-style code reuse attacks. While the case study is small, it indicates, we argue, an approach to rapid-prototyping runtime monitors in hardware that is quick, flexible, and extensible as well as being amenable to formal verification.

Bukasa, Sebanjila K., Lashermes, Ronan, Lanet, Jean-Louis, Leqay, Axel.  2018.  Let's Shock Our IoT's Heart: ARMv7-M Under (Fault) Attacks. Proceedings of the 13th International Conference on Availability, Reliability and Security. :33:1-33:6.

A fault attack is a well-known technique where the behaviour of a chip is voluntarily disturbed by hardware means in order to undermine the security of the information handled by the target. In this paper, we explore how Electromagnetic fault injection (EMFI) can be used to create vulnerabilities in sound software, targeting a Cortex-M3 microcontroller. Several use-cases are shown experimentally: control flow hijacking, buffer overflow (even with the presence of a canary), covert backdoor insertion and Return Oriented Programming can be achieved even if programs are not vulnerable in a software point of view. These results suggest that the protection of any software against vulnerabilities must take hardware into account as well.

Wang, Jingyuan, Xie, Peidai, Wang, Yongjun, Rong, Zelin.  2018.  A Survey of Return-Oriented Programming Attack, Defense and Its Benign Use. 2018 13th Asia Joint Conference on Information Security (AsiaJCIS). :83-88.

The return-oriented programming(ROP) attack has been a common access to exploit software vulnerabilities in the modern operating system(OS). An attacker can execute arbitrary code with the aid of ROP despite security mechanisms are involved in OS. In order to mitigate ROP attack, defense mechanisms are also drawn researchers' attention. Besides, research on the benign use of ROP become a hot spot in recent years, since ROP has a perfect resistance to static analysis, which can be adapted to hide some important code. The results in benign use also benefit from a low overhead on program size. The paper discusses the concepts of ROP attack as well as extended ROP attack in recent years. Corresponding defense mechanisms based on randomization, frequency, and control flow integrity are analyzed as well, besides, we also analyzed limitations in this defense mechanisms. Later, we discussed the benign use of ROP in steganography, code integrity verification, and software watermarking, which showed the significant promotion by adopting ROP. At the end of this paper, we looked into the development of ROP attack, the future of possible mitigation strategies and the potential for benign use.

Farkhani, Reza Mirzazade, Jafari, Saman, Arshad, Sajjad, Robertson, William, Kirda, Engin, Okhravi, Hamed.  2018.  On the Effectiveness of Type-Based Control Flow Integrity. Proceedings of the 34th Annual Computer Security Applications Conference. :28-39.

Control flow integrity (CFI) has received significant attention in the community to combat control hijacking attacks in the presence of memory corruption vulnerabilities. The challenges in creating a practical CFI has resulted in the development of a new type of CFI based on runtime type checking (RTC). RTC-based CFI has been implemented in a number of recent practical efforts such as GRSecurity Reuse Attack Protector (RAP) and LLVM-CFI. While there has been a number of previous efforts that studied the strengths and limitations of other types of CFI techniques, little has been done to evaluate the RTC-based CFI. In this work, we study the effectiveness of RTC from the security and practicality aspects. From the security perspective, we observe that type collisions are abundant in sufficiently large code bases but exploiting them to build a functional attack is not straightforward. Then we show how an attacker can successfully bypass RTC techniques using a variant of ROP attacks that respect type checking (called TROP) and also built two proof-of-concept exploits, one against Nginx web server and the other against Exim mail server. We also discuss practical challenges of implementing RTC. Our findings suggest that while RTC is more practical for applying CFI to large code bases, its policy is not strong enough when facing a motivated attacker.

2019-10-30
Meng, Na, Nagy, Stefan, Yao, Danfeng, Zhuang, Wenjie, Arango-Argoty, Gustavo.  2018.  Secure Coding Practices in Java: Challenges and Vulnerabilities. 2018 IEEE/ACM 40th International Conference on Software Engineering (ICSE). :372-383.

The Java platform and its third-party libraries provide useful features to facilitate secure coding. However, misusing them can cost developers time and effort, as well as introduce security vulnerabilities in software. We conducted an empirical study on StackOverflow posts, aiming to understand developers' concerns on Java secure coding, their programming obstacles, and insecure coding practices. We observed a wide adoption of the authentication and authorization features provided by Spring Security - a third-party framework designed to secure enterprise applications. We found that programming challenges are usually related to APIs or libraries, including the complicated cross-language data handling of cryptography APIs, and the complex Java-based or XML-based approaches to configure Spring Security. In addition, we reported multiple security vulnerabilities in the suggested code of accepted answers on the StackOverflow forum. The vulnerabilities included disabling the default protection against Cross-Site Request Forgery (CSRF) attacks, breaking SSL/TLS security through bypassing certificate validation, and using insecure cryptographic hash functions. Our findings reveal the insufficiency of secure coding assistance and documentation, as well as the huge gap between security theory and coding practices.

Hong, James, Levy, Amit, Riliskis, Laurynas, Levis, Philip.  2018.  Don't Talk Unless I Say So! Securing the Internet of Things with Default-Off Networking. 2018 IEEE/ACM Third International Conference on Internet-of-Things Design and Implementation (IoTDI). :117-128.

The Internet of Things (IoT) is changing the way we interact with everyday objects. "Smart" devices will reduce energy use, keep our homes safe, and improve our health. However, as recent attacks have shown, these devices also create tremendous security vulnerabilities in our computing networks. Securing all of these devices is a daunting task. In this paper, we argue that IoT device communications should be default-off and desired network communications must be explicitly enabled. Unlike traditional networked applications or devices like a web browser or PC, IoT applications and devices serve narrowly defined purposes and do not require access to all services in the network. Our proposal, Bark, a policy language and runtime for specifying and enforcing minimal access permissions in IoT networks, exploits this fact. Bark phrases access control policies in terms of natural questions (who, what, where, when, and how) and transforms them into transparently enforceable rules for IoT application protocols. Bark can express detailed rules such as "Let the lights see the luminosity of the bedroom sensor at any time" and "Let a device at my front door, if I approve it, unlock my smart lock for 30 seconds" in a way that is presentable and explainable to users. We implement Bark for Wi-Fi/IP and Bluetooth Low Energy (BLE) networks and evaluate its efficacy on several example applications and attacks.

Ghose, Nirnimesh, Lazos, Loukas, Li, Ming.  2018.  Secure Device Bootstrapping Without Secrets Resistant to Signal Manipulation Attacks. 2018 IEEE Symposium on Security and Privacy (SP). :819-835.
In this paper, we address the fundamental problem of securely bootstrapping a group of wireless devices to a hub, when none of the devices share prior associations (secrets) with the hub or between them. This scenario aligns with the secure deployment of body area networks, IoT, medical devices, industrial automation sensors, autonomous vehicles, and others. We develop VERSE, a physical-layer group message integrity verification primitive that effectively detects advanced wireless signal manipulations that can be used to launch man-in-the-middle (MitM) attacks over wireless. Without using shared secrets to establish authenticated channels, such attacks are notoriously difficult to thwart and can undermine the authentication and key establishment processes. VERSE exploits the existence of multiple devices to verify the integrity of the messages exchanged within the group. We then use VERSE to build a bootstrapping protocol, which securely introduces new devices to the network. Compared to the state-of-the-art, VERSE achieves in-band message integrity verification during secure pairing using only the RF modality without relying on out-of-band channels or extensive human involvement. It guarantees security even when the adversary is capable of fully controlling the wireless channel by annihilating and injecting wireless signals. We study the limits of such advanced wireless attacks and prove that the introduction of multiple legitimate devices can be leveraged to increase the security of the pairing process. We validate our claims via theoretical analysis and extensive experimentations on the USRP platform. We further discuss various implementation aspects such as the effect of time synchronization between devices and the effects of multipath and interference. Note that the elimination of shared secrets, default passwords, and public key infrastructures effectively addresses the related key management challenges when these are considered at scale.
Borgolte, Kevin, Hao, Shuang, Fiebig, Tobias, Vigna, Giovanni.  2018.  Enumerating Active IPv6 Hosts for Large-Scale Security Scans via DNSSEC-Signed Reverse Zones. 2018 IEEE Symposium on Security and Privacy (SP). :770-784.

Security research has made extensive use of exhaustive Internet-wide scans over the recent years, as they can provide significant insights into the overall state of security of the Internet, and ZMap made scanning the entire IPv4 address space practical. However, the IPv4 address space is exhausted, and a switch to IPv6, the only accepted long-term solution, is inevitable. In turn, to better understand the security of devices connected to the Internet, including in particular Internet of Things devices, it is imperative to include IPv6 addresses in security evaluations and scans. Unfortunately, it is practically infeasible to iterate through the entire IPv6 address space, as it is 2ˆ96 times larger than the IPv4 address space. Therefore, enumeration of active hosts prior to scanning is necessary. Without it, we will be unable to investigate the overall security of Internet-connected devices in the future. In this paper, we introduce a novel technique to enumerate an active part of the IPv6 address space by walking DNSSEC-signed IPv6 reverse zones. Subsequently, by scanning the enumerated addresses, we uncover significant security problems: the exposure of sensitive data, and incorrectly controlled access to hosts, such as access to routing infrastructure via administrative interfaces, all of which were accessible via IPv6. Furthermore, from our analysis of the differences between accessing dual-stack hosts via IPv6 and IPv4, we hypothesize that the root cause is that machines automatically and by default take on globally routable IPv6 addresses. This is a practice that the affected system administrators appear unaware of, as the respective services are almost always properly protected from unauthorized access via IPv4. Our findings indicate (i) that enumerating active IPv6 hosts is practical without a preferential network position contrary to common belief, (ii) that the security of active IPv6 hosts is currently still lagging behind the security state of IPv4 hosts, and (iii) that unintended IPv6 connectivity is a major security issue for unaware system administrators.

Lewis, Matt.  2018.  Using Graph Databases to Assess the Security of Thingernets Based on the Thingabilities and Thingertivity of Things. Living in the Internet of Things: Cybersecurity of the IoT - 2018. :1-9.

Security within the IoT is currently below par. Common security issues include IoT device vendors not following security best practices and/or omitting crucial security controls and features within their devices, lack of defined and mandated IoT security standards, default IoT device configurations, missing secure update mechanisms to rectify security flaws discovered in IoT devices and the overall unintended consequence of complexity - the attack surface of networks comprising IoT devices can increase exponentially with the addition of each new device. In this paper we set out an approach using graphs and graph databases to understand IoT network complexity and the impact that different devices and their profiles have on the overall security of the underlying network and its associated data.

Lin, Xin, Lei, Lingguang, Wang, Yuewu, Jing, Jiwu, Sun, Kun, Zhou, Quan.  2018.  A Measurement Study on Linux Container Security: Attacks and Countermeasures. Proceedings of the 34th Annual Computer Security Applications Conference. :418-429.

Linux container mechanism has attracted a lot of attention and is increasingly utilized to deploy industry applications. Though it is a consensus that the container mechanism is not secure due to the kernel-sharing property, it lacks a concrete and systematical evaluation on its security using real world exploits. In this paper, we collect an attack dataset including 223 exploits that are effective on the container platform, and classify them into different categories using a two-dimensional attack taxonomy. Then we evaluate the security of existing Linux container mechanism using 88 typical exploits filtered out from the dataset. We find 50 (56.82%) exploits can successfully launch attacks from inside the container with the default configuration. Since the privilege escalation exploits can completely disable the container protection mechanism, we conduct an in-depth analysis on these exploits. We find the kernel security mechanisms such as Capability, Seccomp, and MAC play a more important role in preventing privilege escalation than the container isolation mechanisms (i.e., Namespace and Cgroup). However, the interdependence and mutual-influence relationship among these kernel security mechanisms may make them fall into the "short board effect" and impair their protection capability. By studying the 11 exploits that still can successfully break the isolation provided by container and achieve privilege escalation, we identify a common 4-step attack model followed by all 11 exploits. Finally, we propose a defense mechanism to effectively defeat those identified privilege escalation attacks.

Colesky, Michael, Caiza, Julio C..  2018.  A System of Privacy Patterns for Informing Users: Creating a Pattern System. Proceedings of the 23rd European Conference on Pattern Languages of Programs. :16:1-16:11.

The General Data Protection Regulation mandates data protection in the European Union. This includes data protection by design and having privacy-preserving defaults. This legislation has been in force since May 2018, promising severe consequences for violation. Fulfilling its mandate for data protection is not trivial, though. One approach for realizing this is the use of privacy design patterns. We have recently started consolidating such patterns into useful collections. In this paper we improve a subset of these, constructing a pattern system. This helps to identify contextually appropriate patterns. It better illustrates their application and relation to each other. The pattern system guides software developers, so that they can help users understand how their information system uses personal data. To achieve this, we rewrite our patterns to meet specific requirements. In particular, we add implementability and interconnection, while improving consistency and organization. This results in a system of patterns for informing users.

Loruenser, Thomas, Pöhls, Henrich C., Sell, Leon, Laenger, Thomas.  2018.  CryptSDLC: Embedding Cryptographic Engineering into Secure Software Development Lifecycle. Proceedings of the 13th International Conference on Availability, Reliability and Security. :4:1-4:9.

Application development for the cloud is already challenging because of the complexity caused by the ubiquitous, interconnected, and scalable nature of the cloud paradigm. But when modern secure and privacy aware cloud applications require the integration of cryptographic algorithms, developers even need to face additional challenges: An incorrect application may not only lead to a loss of the intended strong security properties but may also open up additional loopholes for potential breaches some time in the near or far future. To avoid these pitfalls and to achieve dependable security and privacy by design, cryptography needs to be systematically designed into the software, and from scratch. We present a system architecture providing a practical abstraction for the many specialists involved in such a development process, plus a suitable cryptographic software development life cycle methodology on top of the architecture. The methodology is complemented with additional tools supporting structured inter–domain communication and thus the generation of consistent results: cloud security and privacy patterns, and modelling of cloud service level agreements. We conclude with an assessment of the use of the Cryptographic Software Design Life Cycle (CryptSDLC) in a EU research project.

2019-10-23
Ali, Abdullah Ahmed, Zamri Murah, Mohd.  2018.  Security Assessment of Libyan Government Websites. 2018 Cyber Resilience Conference (CRC). :1-4.

Many governments organizations in Libya have started transferring traditional government services to e-government. These e-services will benefit a wide range of public. However, deployment of e-government bring many new security issues. Attackers would take advantages of vulnerabilities in these e-services and would conduct cyber attacks that would result in data loss, services interruptions, privacy loss, financial loss, and other significant loss. The number of vulnerabilities in e-services have increase due to the complexity of the e-services system, a lack of secure programming practices, miss-configuration of systems and web applications vulnerabilities, or not staying up-to-date with security patches. Unfortunately, there is a lack of study being done to assess the current security level of Libyan government websites. Therefore, this study aims to assess the current security of 16 Libyan government websites using penetration testing framework. In this assessment, no exploits were committed or tried on the websites. In penetration testing framework (pen test), there are four main phases: Reconnaissance, Scanning, Enumeration, Vulnerability Assessment and, SSL encryption evaluation. The aim of a security assessment is to discover vulnerabilities that could be exploited by attackers. We also conducted a Content Analysis phase for all websites. In this phase, we searched for security and privacy policies implementation information on the government websites. The aim is to determine whether the websites are aware of current accepted standard for security and privacy. From our security assessment results of 16 Libyan government websites, we compared the websites based on the number of vulnerabilities found and the level of security policies. We only found 9 websites with high and medium vulnerabilities. Many of these vulnerabilities are due to outdated software and systems, miss-configuration of systems and not applying the latest security patches. These vulnerabilities could be used by cyber hackers to attack the systems and caused damages to the systems. Also, we found 5 websites didn't implement any SSL encryption for data transactions. Lastly, only 2 websites have published security and privacy policies on their websites. This seems to indicate that these websites were not concerned with current standard in security and privacy. Finally, we classify the 16 websites into 4 safety categories: highly unsafe, unsafe, somewhat unsafe and safe. We found only 1 website with a highly unsafe ranking. Based on our finding, we concluded that the security level of the Libyan government websites are adequate, but can be further improved. However, immediate actions need to be taken to mitigate possible cyber attacks by fixing the vulnerabilities and implementing SSL encryption. Also, the websites need to publish their security and privacy policy so the users could trust their websites.

Madala, D S V, Jhanwar, Mahabir Prasad, Chattopadhyay, Anupam.  2018.  Certificate Transparency Using Blockchain. 2018 IEEE International Conference on Data Mining Workshops (ICDMW). :71-80.

The security of web communication via the SSL/TLS protocols relies on safe distributions of public keys associated with web domains in the form of X.509 certificates. Certificate authorities (CAs) are trusted third parties that issue these certificates. However, the CA ecosystem is fragile and prone to compromises. Starting with Google's Certificate Transparency project, a number of research works have recently looked at adding transparency for better CA accountability, effectively through public logs of all certificates issued by certification authorities, to augment the current X.509 certificate validation process into SSL/TLS. In this paper, leveraging recent progress in blockchain technology, we propose a novel system, called CTB, that makes it impossible for a CA to issue a certificate for a domain without obtaining consent from the domain owner. We further make progress to equip CTB with certificate revocation mechanism. We implement CTB using IBM's Hyperledger Fabric blockchain platform. CTB's smart contract, written in Go, is provided for complete reference.

Szalachowski, Pawel.  2018.  (Short Paper) Towards More Reliable Bitcoin Timestamps. 2018 Crypto Valley Conference on Blockchain Technology (CVCBT). :101-104.

Bitcoin provides freshness properties by forming a blockchain where each block is associated with its timestamp and the previous block. Due to these properties, the Bitcoin protocol is being used as a decentralized, trusted, and secure timestamping service. Although Bitcoin participants which create new blocks cannot modify their order, they can manipulate timestamps almost undetected. This undermines the Bitcoin protocol as a reliable timestamping service. In particular, a newcomer that synchronizes the entire blockchain has a little guarantee about timestamps of all blocks. In this paper, we present a simple yet powerful mechanism that increases the reliability of Bitcoin timestamps. Our protocol can provide evidence that a block was created within a certain time range. The protocol is efficient, backward compatible, and surprisingly, currently deployed SSL/TLS servers can act as reference time sources. The protocol has many applications and can be used for detecting various attacks against the Bitcoin protocol.

Chen, Jing, Yao, Shixiong, Yuan, Quan, He, Kun, Ji, Shouling, Du, Ruiying.  2018.  CertChain: Public and Efficient Certificate Audit Based on Blockchain for TLS Connections. IEEE INFOCOM 2018 - IEEE Conference on Computer Communications. :2060-2068.

In recent years, real-world attacks against PKI take place frequently. For example, malicious domains' certificates issued by compromised CAs are widespread, and revoked certificates are still trusted by clients. In spite of a lot of research to improve the security of SSL/TLS connections, there are still some problems unsolved. On one hand, although log-based schemes provided certificate audit service to quickly detect CAs' misbehavior, the security and data consistency of log servers are ignored. On the other hand, revoked certificates checking is neglected due to the incomplete, insecure and inefficient certificate revocation mechanisms. Further, existing revoked certificates checking schemes are centralized which would bring safety bottlenecks. In this paper, we propose a blockchain-based public and efficient audit scheme for TLS connections, which is called Certchain. Specially, we propose a dependability-rank based consensus protocol in our blockchain system and a new data structure to support certificate forward traceability. Furthermore, we present a method that utilizes dual counting bloom filter (DCBF) with eliminating false positives to achieve economic space and efficient query for certificate revocation checking. The security analysis and experimental results demonstrate that CertChain is suitable in practice with moderate overhead.

Lee, Hojoon, Song, Chihyun, Kang, Brent Byunghoon.  2018.  Lord of the X86 Rings: A Portable User Mode Privilege Separation Architecture on X86. Proceedings of the 2018 ACM SIGSAC Conference on Computer and Communications Security. :1441-1454.

Modern applications often involve processing of sensitive information. However, the lack of privilege separation within the user space leaves sensitive application secret such as cryptographic keys just as unprotected as a "hello world" string. Cutting-edge hardware-supported security features are being introduced. However, the features are often vendor-specific or lack compatibility with older generations of the processors. The situation leaves developers with no portable solution to incorporate protection for the sensitive application component. We propose LOTRx86, a fundamental and portable approach for user-space privilege separation. Our approach creates a more privileged user execution layer called PrivUser by harnessing the underused intermediate privilege levels on the x86 architecture. The PrivUser memory space, a set of pages within process address space that are inaccessible to user mode, is a safe place for application secrets and routines that access them. We implement the LOTRx86 ABI that exports the privcall interface to users to invoke secret handling routines in PrivUser. This way, sensitive application operations that involve the secrets are performed in a strictly controlled manner. The memory access control in our architecture is privilege-based, accessing the protected application secret only requires a change in the privilege, eliminating the need for costly remote procedure calls or change in address space. We evaluated our platform by developing a proof-of-concept LOTRx86-enabled web server that employs our architecture to securely access its private key during an SSL connection. We conducted a set of experiments including a performance measurement on the PoC on both Intel and AMD PCs, and confirmed that LOTRx86 incurs only a limited performance overhead.

Alshawish, Ali, Spielvogel, Korbinian, de Meer, Hermann.  2019.  A Model-Based Time-to-Compromise Estimator to Assess the Security Posture of Vulnerable Networks. 2019 International Conference on Networked Systems (NetSys). :1-3.

Several operational and economic factors impact the patching decisions of critical infrastructures. The constraints imposed by such factors could prevent organizations from fully remedying all of the vulnerabilities that expose their (critical) assets to risk. Therefore, an involved decision maker (e.g. security officer) has to strategically decide on the allocation of possible remediation efforts towards minimizing the inherent security risk. This, however, involves the use of comparative judgments to prioritize risks and remediation actions. Throughout this work, the security risk is quantified using the security metric Time-To-Compromise (TTC). Our main contribution is to provide a generic TTC estimator to comparatively assess the security posture of computer networks taking into account interdependencies between the network components, different adversary skill levels, and characteristics of (known and zero-day) vulnerabilities. The presented estimator relies on a stochastic TTC model and Monte Carlo simulation (MCS) techniques to account for the input data variability and inherent prediction uncertainties.