Wang, Xi-Kun, Sun, Xin.
2021.
CP-ABE with Efficient Revocation Based on the KEK Tree in Data Outsourcing System. 2021 40th Chinese Control Conference (CCC). :8610–8615.
CP-ABE (ciphertext-policy attribute-based encryption) is a promising encryption scheme. In this paper, a highly expressive revocable scheme based on the key encryption keys (KEK) tree is proposed. In this method, the cloud server realizes the cancellation of attribute-level users and effectively reduces the computational burden of the data owner and attribute authority. This scheme embeds a unique random value associated with the user in the attribute group keys. The attribute group keys of each user are different, and it is impossible to initiate a collusion attack. Computing outsourcing makes most of the decryption work done by the cloud server, and the data user only need to perform an exponential operation; in terms of security, the security proof is completed under the standard model based on simple assumptions. Under the premise of ensuring security, the scheme in this paper has the functions of revocation and traceability, and the speed of decryption calculation is also improved.
Ying, Xuhang, Bernieri, Giuseppe, Conti, Mauro, Bushnell, Linda, Poovendran, Radha.
2021.
Covert Channel-Based Transmitter Authentication in Controller Area Networks. IEEE Transactions on Dependable and Secure Computing. :1–1.
In recent years, the security of automotive Cyber-Physical Systems (CPSs) is facing urgent threats due to the widespread use of legacy in-vehicle communication systems. As a representative legacy bus system, the Controller Area Network (CAN) hosts Electronic Control Units (ECUs) that are crucial for the vehicles functioning. In this scenario, malicious actors can exploit the CAN vulnerabilities, such as the lack of built-in authentication and encryption schemes, to launch CAN bus attacks. In this paper, we present TACAN (Transmitter Authentication in CAN), which provides secure authentication of ECUs on the legacy CAN bus by exploiting the covert channels. TACAN turns upside-down the originally malicious concept of covert channels and exploits it to build an effective defensive technique that facilitates transmitter authentication. TACAN consists of three different covert channels: 1) Inter-Arrival Time (IAT)-based, 2) Least Significant Bit (LSB)-based, and 3) hybrid covert channels. In order to validate TACAN, we implement the covert channels on the University of Washington (UW) EcoCAR (Chevrolet Camaro 2016) testbed. We further evaluate the bit error, throughput, and detection performance of TACAN through extensive experiments using the EcoCAR testbed and a publicly available dataset collected from Toyota Camry 2010.
Conference Name: IEEE Transactions on Dependable and Secure Computing
Bullock, Michael S., Gagatsos, Christos N., Bash, Boulat A..
2021.
Capacity Theorems for Covert Bosonic Channels. 2020 IEEE Information Theory Workshop (ITW). :1–5.
We study quantum-secure covert-communication over lossy thermal-noise bosonic channels, the quantum mechanical model for many practical channels. We derive the expressions for the covert capacity of these channels: Lno-EA, when Alice and Bob share only a classical secret, and LEA, when they benefit from entanglement assistance. Entanglement assistance alters the fundamental scaling law for covert communication. Instead of Lno-EA$\surd$n-rno-EA(n), rno-EA(n) = o($\surd$n), entanglement assistance allows LEA$\surd$n log n - rEA(n), rEA(n) = o($\surd$n log n), covert bits to be transmitted reliably over n channel uses. However, noise in entanglement storage erases the log n gain from our achievability; work on the matching converse is ongoing.
Dani, Vidyalaxmi, Ramaiyan, Venkatesh, Jalihal, Devendra.
2021.
Covert Communication over Asynchronous Channels with Timing Advantage. 2021 IEEE Information Theory Workshop (ITW). :1–6.
We study a problem of covert communication over binary symmetric channels (BSC) in an asynchronous setup. Here, Alice seeks to communicate to Bob over a BSC while trying to be covert with respect to Willie, who observes any communication through possibly a different BSC. When Alice communicates, she transmits a message (using a codeword of length n) at a random time uniformly distributed in a window of size Aw slots. We assume that Bob has side information about the time of transmission leading to a reduced uncertainty of Ab slots for Bob, where \$A\_b$\backslash$lt A\_w\$. In this setup, we seek to characterize the limits of covert communication as a function of the timing advantage. When Aw is increasing exponentially in n, we characterize the covert capacity as a function of Aw and Ab. When Aw is increasing sub-exponentially in n, we characterize lower and upper bounds on achievable covert bits and show that positive covert rates are not feasible irrespective of timing advantage. Using numerical work, we illustrate our results for different network scenarios, and also highlight a tradeoff between timing advantage and channel advantage (between Bob and Willie).
Zhang, Qiaosheng, Tan, Vincent Y. F..
2021.
Covert Identification Over Binary-Input Discrete Memoryless Channels. IEEE Transactions on Information Theory. 67:5387–5403.
This paper considers the covert identification problem in which a sender aims to reliably convey an identification (ID) message to a set of receivers via a binary-input discrete memoryless channel (BDMC), and simultaneously to guarantee that the communication is covert with respect to a warden who monitors the communication via another independent BDMC. We prove a square-root law for the covert identification problem. This states that an ID message of size exp(exp($\Theta$($\surd$ n)) can be transmitted over n channel uses. We then characterize the exact pre-constant in the $\Theta$($\cdot$) notation. This constant is referred to as the covert identification capacity. We show that it equals the recently developed covert capacity in the standard covert communication problem, and somewhat surprisingly, the covert identification capacity can be achieved without any shared key between the sender and receivers. The achievability proof relies on a random coding argument with pulse-position modulation (PPM), coupled with a second stage which performs code refinements. The converse proof relies on an expurgation argument as well as results for channel resolvability with stringent input constraints.
Conference Name: IEEE Transactions on Information Theory
Shahzad, Khurram, Zhou, Xiangyun.
2021.
Covert Wireless Communications Under Quasi-Static Fading With Channel Uncertainty. IEEE Transactions on Information Forensics and Security. 16:1104–1116.
Covert communications enable a transmitter to send information reliably in the presence of an adversary, who looks to detect whether the transmission took place or not. We consider covert communications over quasi-static block fading channels, where users suffer from channel uncertainty. We investigate the adversary Willie's optimal detection performance in two extreme cases, i.e., the case of perfect channel state information (CSI) and the case of channel distribution information (CDI) only. It is shown that in the large detection error regime, Willie's detection performances of these two cases are essentially indistinguishable, which implies that the quality of CSI does not help Willie in improving his detection performance. This result enables us to study the covert transmission design without the need to factor in the exact amount of channel uncertainty at Willie. We then obtain the optimal and suboptimal closed-form solution to the covert transmission design. Our result reveals fundamental difference in the design between the case of quasi-static fading channel and the previously studied case of non-fading AWGN channel.
Conference Name: IEEE Transactions on Information Forensics and Security
Giechaskiel, Ilias, Tian, Shanquan, Szefer, Jakub.
2021.
Cross-VM Information Leaks in FPGA-Accelerated Cloud Environments. 2021 IEEE International Symposium on Hardware Oriented Security and Trust (HOST). :91–101.
The availability of FPGAs in cloud data centers offers rapid, on-demand access to hardware compute resources that users can configure to their own needs. However, the low-level access to the hardware FPGA and associated resources such as PCIe, SSD, or DRAM also opens up threats of malicious attackers uploading designs that are able to infer information about other users or about the cloud infrastructure itself. In particular, this work presents a new, fast PCIe-contention-based channel that is able to transmit data between different FPGA-accelerated virtual machines with bandwidths reaching 2 kbps with 97% accuracy. This paper further demonstrates that the PCIe receiver circuits are able to not just receive covert transmissions, but can also perform fine-grained monitoring of the PCIe bus or detect different types of activities from other users' FPGA-accelerated virtual machines based on their PCIe traffic signatures. Beyond leaking information across different virtual machines, the ability to monitor the PCIe bandwidth over hours or days can be used to estimate the data center utilization and map the behavior of the other users. The paper also introduces further novel threats in FPGA-accelerated instances, including contention due to shared NVMe SSDs as well as thermal monitoring to identify FPGA co-location using the DRAM modules attached to the FPGA boards. This is the first work to demonstrate that it is possible to break the separation of privilege in FPGA-accelerated cloud environments, and highlights that defenses for public clouds using FPGAs need to consider PCIe, SSD, and DRAM resources as part of the attack surface that should be protected.
Wai, Fok Kar, Thing, Vrizlynn L. L..
2021.
Clustering Based Opcode Graph Generation for Malware Variant Detection. 2021 18th International Conference on Privacy, Security and Trust (PST). :1–11.
Malwares are the key means leveraged by threat actors in the cyber space for their attacks. There is a large array of commercial solutions in the market and significant scientific research to tackle the challenge of the detection and defense against malwares. At the same time, attackers also advance their capabilities in creating polymorphic and metamorphic malwares to make it increasingly challenging for existing solutions. To tackle this issue, we propose a methodology to perform malware detection and family attribution. The proposed methodology first performs the extraction of opcodes from malwares in each family and constructs their respective opcode graphs. We explore the use of clustering algorithms on the opcode graphs to detect clusters of malwares within the same malware family. Such clusters can be seen as belonging to different sub-family groups. Opcode graph signatures are built from each detected cluster. Hence, for each malware family, a group of signatures is generated to represent the family. These signatures are used to classify an unknown sample as benign or belonging to one the malware families. We evaluate our methodology by performing experiments on a dataset consisting of both benign files and malware samples belonging to a number of different malware families and comparing the results to existing approach.
Garn, Bernhard, Sebastian Lang, Daniel, Leithner, Manuel, Richard Kuhn, D., Kacker, Raghu, Simos, Dimitris E..
2021.
Combinatorially XSSing Web Application Firewalls. 2021 IEEE International Conference on Software Testing, Verification and Validation Workshops (ICSTW). :85–94.
Cross-Site scripting (XSS) is a common class of vulnerabilities in the domain of web applications. As it re-mains prevalent despite continued efforts by practitioners and researchers, site operators often seek to protect their assets using web application firewalls (WAFs). These systems employ filtering mechanisms to intercept and reject requests that may be suitable to exploit XSS flaws and related vulnerabilities such as SQL injections. However, they generally do not offer complete protection and can often be bypassed using specifically crafted exploits. In this work, we evaluate the effectiveness of WAFs to detect XSS exploits. We develop an attack grammar and use a combinatorial testing approach to generate attack vectors. We compare our vectors with conventional counterparts and their ability to bypass different WAFs. Our results show that the vectors generated with combinatorial testing perform equal or better in almost all cases. They further confirm that most of the rule sets evaluated in this work can be bypassed by at least one of these crafted inputs.
Farea, Abdulgbar A. R., Wang, Chengliang, Farea, Ebraheem, Ba Alawi, Abdulfattah.
2021.
Cross-Site Scripting (XSS) and SQL Injection Attacks Multi-classification Using Bidirectional LSTM Recurrent Neural Network. 2021 IEEE International Conference on Progress in Informatics and Computing (PIC). :358–363.
E-commerce, ticket booking, banking, and other web-based applications that deal with sensitive information, such as passwords, payment information, and financial information, are widespread. Some web developers may have different levels of understanding about securing an online application. The two vulnerabilities identified by the Open Web Application Security Project (OWASP) for its 2017 Top Ten List are SQL injection and Cross-site Scripting (XSS). Because of these two vulnerabilities, an attacker can take advantage of these flaws and launch harmful web-based actions. Many published articles concentrated on a binary classification for these attacks. This article developed a new approach for detecting SQL injection and XSS attacks using deep learning. SQL injection and XSS payloads datasets are combined into a single dataset. The word-embedding technique is utilized to convert the word’s text into a vector. Our model used BiLSTM to auto feature extraction, training, and testing the payloads dataset. BiLSTM classified the payloads into three classes: XSS, SQL injection attacks, and normal. The results showed great results in classifying payloads into three classes: XSS attacks, injection attacks, and non-malicious payloads. BiLSTM showed high performance reached 99.26% in terms of accuracy.