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2017-04-03
Lee, Seungsoo, Yoon, Changhoon, Shin, Seungwon.  2016.  The Smaller, the Shrewder: A Simple Malicious Application Can Kill an Entire SDN Environment. Proceedings of the 2016 ACM International Workshop on Security in Software Defined Networks & Network Function Virtualization. :23–28.

Security vulnerability assessment is an important process that must be conducted against any system before the deployment, and emerging technologies are no exceptions. Software-Defined Networking (SDN) has aggressively evolved in the past few years and is now almost at the early adoption stage. At this stage, the attack surface of SDN should be thoroughly investigated and assessed in order to mitigate possible security breaches against SDN. Inspired by the necessity, we reveal three attack scenarios that leverage SDN application to attack SDNs, and test the attack scenarios against three of the most popular SDN controllers available today. In addition, we discuss the possible defense mechanisms against such application-originated attacks.

Hastings, Marcella, Fried, Joshua, Heninger, Nadia.  2016.  Weak Keys Remain Widespread in Network Devices. Proceedings of the 2016 Internet Measurement Conference. :49–63.

In 2012, two academic groups reported having computed the RSA private keys for 0.5% of HTTPS hosts on the internet, and traced the underlying issue to widespread random number generation failures on networked devices. The vulnerability was reported to dozens of vendors, several of whom responded with security advisories, and the Linux kernel was patched to fix a boottime entropy hole that contributed to the failures. In this paper, we measure the actions taken by vendors and end users over time in response to the original disclosure. We analyzed public internet-wide TLS scans performed between July 2010 and May 2016 and extracted 81 million distinct RSA keys. We then computed the pairwise common divisors for the entire set in order to factor over 313,000 keys vulnerable to the aw, and fingerprinted implementations to study patching behavior over time across vendors. We find that many vendors appear to have never produced a patch, and observed little to no patching behavior by end users of affected devices. The number of vulnerable hosts increased in the years after notification and public disclosure, and several newly vulnerable implementations have appeared since 2012. Vendor notification, positive vendor responses, and even vendor-produced public security advisories appear to have little correlation with end-user security.

Nicol, David M..  2016.  Risk Assessment of Cyber Access to Physical Infrastructure in Cyber-Physical Systems. Proceedings of the 2Nd ACM International Workshop on Cyber-Physical System Security. :1–2.
Medwed, Marcel.  2016.  IoT Security Challenges and Ways Forward. Proceedings of the 6th International Workshop on Trustworthy Embedded Devices. :55–55.

Today 2.9 billion people, or 40% of the world's population are online. By 2020, at least 40 billion more devices will become smart via embedded processors. The impact of such Internet of Things (IoT) on our society will be extraordinary. It will influence most consumer and business sectors, impact education, healthcare and safety. However, it certainly will also pose a challenge from a security point of view. Not only will the devices themselves become more complex, also the interaction between devices, the networks and the variance in topology will grow. Finally, with increasing amounts of data and assets at stake the incentive for attackers will increase. The costs of cyber attacks in such setting are estimated to reach about 2 trillion USD by 2020. Today, the IoT is just beginning to emerge. Unfortunately, when looking at its security, there is lots of room for improvement. Exploits reported at a steady pace clearly suggest that security is a major challenge when the world wants to successfully switch from an IoT hype to a real IoT deployment. Security, and security risk awareness, insufficiently present in today's consumer and developer mindset, are only a starting point. Once the requirement for strong security is widely accepted, there will be still the economical question of who is going to pay for security and its maintenance. Without enforcing certain standards by means of third party evaluation this problem is expected to be hard to get under control.

Combs-Ford, Marcia.  2016.  Security Assessment of Industrial Control Supervisory and Process Control Zones. Proceedings of the 17th Annual Conference on Information Technology Education. :73–76.

With the discovery of the Stuxnet malware in June 2010, Industrial Control System (ICS) security has gained global attention and scrutiny. Due to the unique industrial control operating environment, standard information technology host-based defenses such as operating system upgrades are not always feasible. Therefore, ICS security strategies must rely upon layered network infrastructure and enclave boundary defenses. As ICS threats evolve, so too must ICS security practices and strategies. ICS security innovation rely upon understanding the effectiveness of established defenses and countermeasures. In an effort to evaluate the security effectiveness of ICS layered perimeter defenses, a Red Team security assessment was conducted on an ICS test network. This experiment offers insight to the effectiveness of ICS perimeter defenses by demonstrating the reduction of attack vectors, decreased adversarial network access, and perimeter network defenses are an effective ICS security strategy.

Genkin, Daniel, Pachmanov, Lev, Pipman, Itamar, Tromer, Eran, Yarom, Yuval.  2016.  ECDSA Key Extraction from Mobile Devices via Nonintrusive Physical Side Channels. Proceedings of the 2016 ACM SIGSAC Conference on Computer and Communications Security. :1626–1638.

We show that elliptic-curve cryptography implementations on mobile devices are vulnerable to electromagnetic and power side-channel attacks. We demonstrate full extraction of ECDSA secret signing keys from OpenSSL and CoreBitcoin running on iOS devices, and partial key leakage from OpenSSL running on Android and from iOS's CommonCrypto. These non-intrusive attacks use a simple magnetic probe placed in proximity to the device, or a power probe on the phone's USB cable. They use a bandwidth of merely a few hundred kHz, and can be performed cheaply using an audio card and an improvised magnetic probe.

Frey, Sylvain, Rashid, Awais, Zanutto, Alberto, Busby, Jerry, Follis, Karolina.  2016.  On the Role of Latent Design Conditions in Cyber-physical Systems Security. Proceedings of the 2Nd International Workshop on Software Engineering for Smart Cyber-Physical Systems. :43–46.

As cyber-physical systems (CPS) become prevalent in everyday life, it is critical to understand the factors that may impact the security of such systems. In this paper, we present insights from an initial study of historical security incidents to analyse such factors for a particular class of CPS: industrial control systems (ICS). Our study challenges the usual tendency to blame human fallibility or resort to simple explanations for what are often complex issues that lead to a security incident. We highlight that (i) perception errors are key in such incidents (ii) latent design conditions – e.g., improper specifications of a system's borders and capabilities – play a fundamental role in shaping perceptions, leading to security issues. Such design-time considerations are particularly critical for ICS, the life-cycle of which is usually measured in decades. Based on this analysis, we discuss how key characteristics of future smart CPS in such industrial settings can pose further challenges with regards to tackling latent design flaws.

Mahfouzi, Rouhollah, Aminifar, Amir, Eles, Petru, Peng, Zebo, Villani, Mattias.  2016.  Intrusion-Damage Assessment and Mitigation in Cyber-Physical Systems for Control Applications. Proceedings of the 24th International Conference on Real-Time Networks and Systems. :141–150.

With cyber-physical systems opening to the outside world, security can no longer be considered a secondary issue. One of the key aspects in security of cyber-phyiscal systems is to deal with intrusions. In this paper, we highlight the several unique properties of control applications in cyber-physical systems. Using these unique properties, we propose a systematic intrusion-damage assessment and mitigation mechanism for the class of observable and controllable attacks. On the one hand, in cyber-physical systems, the plants follow certain laws of physics and this can be utilized to address the intrusion-damage assessment problem. That is, the states of the controlled plant should follow those expected according to the physics of the system and any major discrepancy is potentially an indication of intrusion. Here, we use a machine learning algorithm to capture the normal behavior of the system according to its dynamics. On the other hand, the control performance strongly depends on the amount of allocated resources and this can be used to address the intrusion-damage mitigation problem. That is, the intrusion-damage mitigation is based on the idea of allocating more resources to the control application under attack. This is done using a feedback-based approach including a convex optimization.

Moore, Samuel, Yampolskiy, Mark, Gatlin, Jacob, McDonald, Jeffrey T., Andel, Todd R..  2016.  Buffer Overflow Attack's Power Consumption Signatures. Proceedings of the 6th Workshop on Software Security, Protection, and Reverse Engineering. :6:1–6:7.

Embedded Systems (ES) are an integral part of Cyber-Physical Systems (CPS), the Internet of Things (IoT), and consumer devices like smartphones. ES often have limited resources, and - if used in CPS and IoT - have to satisfy real time requirements. Therefore, ES rarely employ the security measures established for computer systems and networks. Due to the growth of both CPS and IoT it is important to identify ongoing attacks on ES without interfering with realtime constraints. Furthermore, security solutions that can be retrofit to legacy systems are desirable, especially when ES are used in Industrial Control Systems (ICS) that often maintain the same hardware for decades. To tackle this problem, several researchers have proposed using side-channels (i.e., physical emanations accompanying cyber processes) to detect such attacks. While prior work focuses on the anomaly detection approach, this might not always be sufficient, especially in complex ES whose behavior depends on the input data. In this paper, we determine whether one of the most common attacks - a buffer overflow attack - generates distinct side-channel signatures if executed on a vulnerable ES. We only consider the power consumption side-channel. We collect and analyze power traces from normal program operation and four cases of buffer overflow attack categories: (i) crash program execution, (ii) injection of executable code, (iii) return to existing function, and (iv) Return Oriented Programming (ROP) with gadgets. Our analysis shows that for some of these cases a power signature-based detection of a buffer overflow attack is possible.

Chhetri, Sujit Rokka, Canedo, Arquimedes, Faruque, Mohammad Abdullah Al.  2016.  KCAD: Kinetic Cyber-attack Detection Method for Cyber-physical Additive Manufacturing Systems. Proceedings of the 35th International Conference on Computer-Aided Design. :74:1–74:8.

Additive Manufacturing (AM) uses Cyber-Physical Systems (CPS) (e.g., 3D Printers) that are vulnerable to kinetic cyber-attacks. Kinetic cyber-attacks cause physical damage to the system from the cyber domain. In AM, kinetic cyber-attacks are realized by introducing flaws in the design of the 3D objects. These flaws may eventually compromise the structural integrity of the printed objects. In CPS, researchers have designed various attack detection method to detect the attacks on the integrity of the system. However, in AM, attack detection method is in its infancy. Moreover, analog emissions (such as acoustics, electromagnetic emissions, etc.) from the side-channels of AM have not been fully considered as a parameter for attack detection. To aid the security research in AM, this paper presents a novel attack detection method that is able to detect zero-day kinetic cyber-attacks on AM by identifying anomalous analog emissions which arise as an outcome of the attack. This is achieved by statistically estimating functions that map the relation between the analog emissions and the corresponding cyber domain data (such as G-code) to model the behavior of the system. Our method has been tested to detect potential zero-day kinetic cyber-attacks in fused deposition modeling based AM. These attacks can physically manifest to change various parameters of the 3D object, such as speed, dimension, and movement axis. Accuracy, defined as the capability of our method to detect the range of variations introduced to these parameters as a result of kinetic cyber-attacks, is 77.45%.

Wadhawan, Yatin, Neuman, Clifford.  2016.  Defending Cyber-Physical Attacks on Oil Pipeline Systems: A Game-Theoretic Approach. Proceedings of the 1st International Workshop on AI for Privacy and Security. :7:1–7:8.

The security of critical infrastructures such as oil and gas cyber-physical systems is a significant concern in today's world where malicious activities are frequent like never before. On one side we have cyber criminals who compromise cyber infrastructure to control physical processes; we also have physical criminals who attack the physical infrastructure motivated to destroy the target or to steal oil from pipelines. Unfortunately, due to limited resources and physical dispersion, it is impossible for the system administrator to protect each target all the time. In this research paper, we tackle the problem of cyber and physical attacks on oil pipeline infrastructure by proposing a Stackelberg Security Game of three players: system administrator as a leader, cyber and physical attackers as followers. The novelty of this paper is that we have formulated a real world problem of oil stealing using a game theoretic approach. The game has two different types of targets attacked by two distinct types of adversaries with different motives and who can coordinate to maximize their rewards. The solution to this game assists the system administrator of the oil pipeline cyber-physical system to allocate the cyber security controls for the cyber targets and to assign patrol teams to the pipeline regions efficiently. This paper provides a theoretical framework for formulating and solving the above problem.

Moser, Daniel, Leu, Patrick, Lenders, Vincent, Ranganathan, Aanjhan, Ricciato, Fabio, Capkun, Srdjan.  2016.  Investigation of Multi-device Location Spoofing Attacks on Air Traffic Control and Possible Countermeasures. Proceedings of the 22Nd Annual International Conference on Mobile Computing and Networking. :375–386.

Multilateration techniques have been proposed to verify the integrity of unprotected location claims in wireless localization systems. A common assumption is that the adversary is equipped with only a single device from which it transmits location spoofing signals. In this paper, we consider a more advanced model where the attacker is equipped with multiple devices and performs a geographically distributed coordinated attack on the multilateration system. The feasibility of a distributed multi-device attack is demonstrated experimentally with a self-developed attack implementation based on multiple COTS software-defined radio (SDR) devices. We launch an attack against the OpenSky Network, an air traffic surveillance system that implements a time-difference-of-arrival (TDoA) multi-lateration method for aircraft localization based on ADS-B signals. Our experiments show that the timing errors for distributed spoofed signals are indistinguishable from the multilateration errors of legitimate aircraft signals, indicating that the threat of multi-device spoofing attacks is real in this and other similar systems. In the second part of this work, we investigate physical-layer features that could be used to detect multi-device attacks. We show that the frequency offset and transient phase noise of the attacker's radio devices can be exploited to discriminate between a received signal that has been transmitted by a single (legitimate) transponder or by multiple (malicious) spoofing sources. Based on that, we devise a multi-device spoofing detection system that achieves zero false positives and a false negative rate below 1%.

Classen, Jiska, Steinmetzer, Daniel, Hollick, Matthias.  2016.  Opportunities and Pitfalls in Securing Visible Light Communication on the Physical Layer. Proceedings of the 3rd Workshop on Visible Light Communication Systems. :19–24.

Securing visible light communication (VLC) systems on the physical layer promises to prevent against a variety of attacks. Recent work shows that the adaption of existing legacy radio wave physical layer security (PLS) mechanisms is possible with minor changes. Yet, many adaptations open new vulnerabilities due to distinct propagation characteristics of visible light. A common understanding of threats arising from various attacker capabilities is missing. We specify a new attacker model for visible light physical layer attacks and evaluate the applicability of existing PLS approaches. Our results show that many attacks are not considered in current solutions.

Zenger, Christian T., Zimmer, Jan, Pietersz, Mario, Driessen, Benedikt, Paar, Christof.  2016.  Constructive and Destructive Aspects of Adaptive Wormholes for the 5G Tactile Internet. Proceedings of the 9th ACM Conference on Security & Privacy in Wireless and Mobile Networks. :109–120.

In this work, we constructively combine adaptive wormholes with channel-reciprocity based key establishment (CRKE), which has been proposed as a lightweight security solution for IoT devices and might be even more important for the 5G Tactile Internet and its embedded low-end devices. We present a new secret key generation protocol where two parties compute shared cryptographic keys under narrow-band multi-path fading models over a delayed digital channel. The proposed approach furthermore enables distance-bounding the key establishment process via the coherence time dependencies of the wireless channel. Our scheme is thoroughly evaluated both theoretically and practically. For the latter, we used a testbed based on the IEEE 802.15.4 standard and performed extensive experiments in a real-world manufacturing environment. Additionally, we demonstrate adaptive wormhole attacks (AWOAs) and their consequences on several physical-layer security schemes. Furthermore, we proposed a countermeasure that minimizes the risk of AWOAs.

Zheng, Yao, Schulz, Matthias, Lou, Wenjing, Hou, Y. Thomas, Hollick, Matthias.  2016.  Profiling the Strength of Physical-Layer Security: A Study in Orthogonal Blinding. Proceedings of the 9th ACM Conference on Security & Privacy in Wireless and Mobile Networks. :21–30.

Physical layer security for wireless communication is broadly considered as a promising approach to protect data confidentiality against eavesdroppers. However, despite its ample theoretical foundation, the transition to practical implementations of physical-layer security still lacks success. A close inspection of proven vulnerable physical-layer security designs reveals that the flaws are usually overlooked when the scheme is only evaluated against an inferior, single-antenna eavesdropper. Meanwhile, the attacks exposing vulnerabilities often lack theoretical justification. To reduce the gap between theory and practice, we posit that a physical-layer security scheme must be studied under multiple adversarial models to fully grasp its security strength. In this regard, we evaluate a specific physical-layer security scheme, i.e. orthogonal blinding, under multiple eavesdropper settings. We further propose a practical "ciphertext-only attack" that allows eavesdroppers to recover the original message by exploiting the low entropy fields in wireless packets. By means of simulation, we are able to reduce the symbol error rate at an eavesdropper below 1% using only the eavesdropper's receiving data and a general knowledge about the format of the wireless packets.

Urbina, David I., Giraldo, Jairo A., Cardenas, Alvaro A., Tippenhauer, Nils Ole, Valente, Junia, Faisal, Mustafa, Ruths, Justin, Candell, Richard, Sandberg, Henrik.  2016.  Limiting the Impact of Stealthy Attacks on Industrial Control Systems. Proceedings of the 2016 ACM SIGSAC Conference on Computer and Communications Security. :1092–1105.

While attacks on information systems have for most practical purposes binary outcomes (information was manipulated/eavesdropped, or not), attacks manipulating the sensor or control signals of Industrial Control Systems (ICS) can be tuned by the attacker to cause a continuous spectrum in damages. Attackers that want to remain undetected can attempt to hide their manipulation of the system by following closely the expected behavior of the system, while injecting just enough false information at each time step to achieve their goals. In this work, we study if attack-detection can limit the impact of such stealthy attacks. We start with a comprehensive review of related work on attack detection schemes in the security and control systems community. We then show that many of those works use detection schemes that are not limiting the impact of stealthy attacks. We propose a new metric to measure the impact of stealthy attacks and how they relate to our selection on an upper bound on false alarms. We finally show that the impact of such attacks can be mitigated in several cases by the proper combination and configuration of detection schemes. We demonstrate the effectiveness of our algorithms through simulations and experiments using real ICS testbeds and real ICS systems.

Purvine, Emilie, Johnson, John R., Lo, Chaomei.  2016.  A Graph-Based Impact Metric for Mitigating Lateral Movement Cyber Attacks. Proceedings of the 2016 ACM Workshop on Automated Decision Making for Active Cyber Defense. :45–52.

Most cyber network attacks begin with an adversary gaining a foothold within the network and proceed with lateral movement until a desired goal is achieved. The mechanism by which lateral movement occurs varies but the basic signature of hopping between hosts by exploiting vulnerabilities is the same. Because of the nature of the vulnerabilities typically exploited, lateral movement is very difficult to detect and defend against. In this paper we define a dynamic reachability graph model of the network to discover possible paths that an adversary could take using different vulnerabilities, and how those paths evolve over time. We use this reachability graph to develop dynamic machine-level and network-level impact scores. Lateral movement mitigation strategies which make use of our impact scores are also discussed, and we detail an example using a freely available data set.

2017-03-29
Stan, Oana, Carpov, Sergiu, Sirdey, Renaud.  2016.  Dynamic Execution of Secure Queries over Homomorphic Encrypted Databases. Proceedings of the 4th ACM International Workshop on Security in Cloud Computing. :51–58.

The wide use of cloud computing and of data outsourcing rises important concerns with regards to data security resulting thus in the necessity of protection mechanisms such as encryption of sensitive data. The recent major theoretical breakthrough of finding the Holy Grail of encryption, i.e. fully homomorphic encryption guarantees the privacy of queries and their results on encrypted data. However, there are only a few studies proposing a practical performance evaluation of the use of homomorphic encryption schemes in order to perform database queries. In this paper, we propose and analyse in the context of a secure framework for a generic database query interpreter two different methods in which client requests are dynamically executed on homomorphically encrypted data. Dynamic compilation of the requests allows to take advantage of the different optimizations performed during an off-line step on an intermediate code representation, taking the form of boolean circuits, and, moreover, to specialize the execution using runtime information. Also, for the returned encrypted results, we assess the complexity and the efficiency of the different protocols proposed in the literature in terms of overall execution time, accuracy and communication overhead.

Mallaiah, Kurra, Gandhi, Rishi Kumar, Ramachandram, S..  2016.  Word and Phrase Proximity Searchable Encryption Protocols for Cloud Based Relational Databases. Proceedings of the International Conference on Internet of Things and Cloud Computing. :42:1–42:12.

In this paper, we propose a practical and efficient word and phrase proximity searchable encryption protocols for cloud based relational databases. The proposed advanced searchable encryption protocols are provably secure. We formalize the security assurance with cryptographic security definitions and prove the security of our searchable encryption protocols under Shannon's perfect secrecy assumption. We have tested the proposed protocols comprehensively on Amazon's high performance computing server using mysql database and presented the results. The proposed protocols ensure that there is zero overhead of space and communication because cipher text size being equal to plaintext size. For the same reason, the database schema also does not change for existing applications. In this paper, we also present results of comprehensive analysis for Song, Wagner, and Perrig scheme.

Zhao, Yunlei.  2016.  Identity-Concealed Authenticated Encryption and Key Exchange. Proceedings of the 2016 ACM SIGSAC Conference on Computer and Communications Security. :1464–1479.

Identity concealment and zero-round trip time (0-RTT) connection are two of current research focuses in the design and analysis of secure transport protocols, like TLS1.3 and Google's QUIC, in the client-server setting. In this work, we introduce a new primitive for identity-concealed authenticated encryption in the public-key setting, referred to as higncryption, which can be viewed as a novel monolithic integration of public-key encryption, digital signature, and identity concealment. We then present the security definitional framework for higncryption, and a conceptually simple (yet carefully designed) protocol construction. As a new primitive, higncryption can have many applications. In this work, we focus on its applications to 0-RTT authentication, showing higncryption is well suitable to and compatible with QUIC and OPTLS, and on its applications to identity-concealed authenticated key exchange (CAKE) and unilateral CAKE (UCAKE). Of independent interest is a new concise security definitional framework for CAKE and UCAKE proposed in this work, which unifies the traditional BR and (post-ID) frameworks, enjoys composability, and ensures very strong security guarantee. Along the way, we make a systematically comparative study with related protocols and mechanisms including Zheng's signcryption, one-pass HMQV, QUIC, TLS1.3 and OPTLS, most of which are widely standardized or in use.

Juretus, Kyle, Savidis, Ioannis.  2016.  Reduced Overhead Gate Level Logic Encryption. Proceedings of the 26th Edition on Great Lakes Symposium on VLSI. :15–20.

Untrusted third-parties are found throughout the integrated circuit (IC) design flow resulting in potential threats in IC reliability and security. Threats include IC counterfeiting, intellectual property (IP) theft, IC overproduction, and the insertion of hardware Trojans. Logic encryption has emerged as a method of enhancing security against such threats, however, current implementations of logic encryption, including the XOR or look-up table (LUT) techniques, have high per-gate overheads in area, performance, and power. A novel gate level logic encryption technique with reduced per-gate overheads is described in this paper. In addition, a technique to expand the search space of a key sequence is provided, increasing the difficulty for an adversary to extract the key value. A power reduction of 41.50%, an estimated area reduction of 43.58%, and a performance increase of 34.54% is achieved when using the proposed gate level logic encryption instead of the LUT based technique for an encrypted AND gate.

Aono, Yoshinori, Hayashi, Takuya, Trieu Phong, Le, Wang, Lihua.  2016.  Scalable and Secure Logistic Regression via Homomorphic Encryption. Proceedings of the Sixth ACM Conference on Data and Application Security and Privacy. :142–144.

Logistic regression is a powerful machine learning tool to classify data. When dealing with sensitive data such as private or medical information, cares are necessary. In this paper, we propose a secure system for protecting the training data in logistic regression via homomorphic encryption. Perhaps surprisingly, despite the non-polynomial tasks of training in logistic regression, we show that only additively homomorphic encryption is needed to build our system. Our system is secure and scalable with the dataset size.

White, Martin, Tufano, Michele, Vendome, Christopher, Poshyvanyk, Denys.  2016.  Deep Learning Code Fragments for Code Clone Detection. Proceedings of the 31st IEEE/ACM International Conference on Automated Software Engineering. :87–98.

Code clone detection is an important problem for software maintenance and evolution. Many approaches consider either structure or identifiers, but none of the existing detection techniques model both sources of information. These techniques also depend on generic, handcrafted features to represent code fragments. We introduce learning-based detection techniques where everything for representing terms and fragments in source code is mined from the repository. Our code analysis supports a framework, which relies on deep learning, for automatically linking patterns mined at the lexical level with patterns mined at the syntactic level. We evaluated our novel learning-based approach for code clone detection with respect to feasibility from the point of view of software maintainers. We sampled and manually evaluated 398 file- and 480 method-level pairs across eight real-world Java systems; 93% of the file- and method-level samples were evaluated to be true positives. Among the true positives, we found pairs mapping to all four clone types. We compared our approach to a traditional structure-oriented technique and found that our learning-based approach detected clones that were either undetected or suboptimally reported by the prominent tool Deckard. Our results affirm that our learning-based approach is suitable for clone detection and a tenable technique for researchers.

Al-Sibahi, Ahmad Salim, Dimovski, Aleksandar S., Wąsowski, Andrzej.  2016.  Symbolic Execution of High-level Transformations. Proceedings of the 2016 ACM SIGPLAN International Conference on Software Language Engineering. :207–220.

Transformations form an important part of developing domain specific languages, where they are used to provide semantics for typing and evaluation. Yet, few solutions exist for verifying transformations written in expressive high-level transformation languages. We take a step towards that goal, by developing a general symbolic execution technique that handles programs written in these high-level transformation languages. We use logical constraints to describe structured symbolic values, including containment, acyclicity, simple unordered collections (sets) and to handle deep type-based querying of syntax hierarchies. We evaluate this symbolic execution technique on a collection of refactoring and model transformation programs, showing that the white-box test generation tool based on symbolic execution obtains better code coverage than a black box test generator for such programs in almost all tested cases.

Afshari, Mehrdad, Su, Zhendong.  2016.  Building White-box Abstractions by Program Refinement. Proceedings of the 2016 ACM International Symposium on New Ideas, New Paradigms, and Reflections on Programming and Software. :74–81.

Abstractions make building complex systems possible. Many facilities provided by a modern programming language are directly designed to build a certain style of abstraction. Abstractions also aim to enhance code reusability, thus enhancing programmer productivity and effectiveness. Real-world software systems can grow to have a complicated hierarchy of abstractions. Often, the hierarchy grows unnecessarily deep, because the programmers have envisioned the most generic use cases for a piece of code to make it reusable. Sometimes, the abstractions used in the program are not the appropriate ones, and it would be simpler for the higher level client to circumvent such abstractions. Another problem is the impedance mismatch between different pieces of code or libraries coming from different projects that are not designed to work together. Interoperability between such libraries are often hindered by abstractions, by design, in the name of hiding implementation details and encapsulation. These problems necessitate forms of abstraction that are easy to manipulate if needed. In this paper, we describe a powerful mechanism to create white-box abstractions, that encourage flatter hierarchies of abstraction and ease of manipulation and customization when necessary: program refinement. In so doing, we rely on the basic principle that writing directly in the host programming language is as least restrictive as one can get in terms of expressiveness, and allow the programmer to reuse and customize existing code snippets to address their specific needs.