Biblio

In the production process of embedded device, due to the frequent reuse of third-party libraries or development kits, there are large number of same vulnerabilities that appear in more than one firmware. Homology analysis is often used in detecting this kind of vulnerabilities caused by code reuse or third-party reuse and in the homology analysis, the widely used methods are mainly Binary difference analysis, Normalized compression distance, String feature matching and Fuzz hash. But when we use these methods for homology analysis, we found that the detection result is not ideal and there is a high false positive rate. Focusing on this problem, we analyzed the application scenarios of these four methods and their limitations by combining different methods and different types of files and the experiments show that the combination of methods and files have a better performance in homology analysis.

Wireless wearable embedded devices dominate the Internet of Things (IoT) due to their ability to provide useful information about the body and its local environment. The constrained resources of low power processors, however, pose a significant challenge to run-time error logging and hence, product reliability. Error logs classify error type and often system state following the occurrence of an error. Traditional error logging algorithms attempt to balance storage and accuracy by selectively overwriting past log entries. Since a specific combination of firmware faults may result in system instability, preserving all error occurrences becomes increasingly beneficial as IOT systems become more complex. In this paper, a novel hash-based error logging algorithm is presented which has both constant insertion time and constant memory while also exhibiting no false negatives and an acceptable false positive error rate. Both theoretical analysis and simulations are used to compare the performance of the hash-based and traditional approaches.

Highly privileged software, such as firmware, is an attractive target for attackers. Thus, BIOS vendors use cryptographic signatures to ensure firmware integrity at boot time. Nevertheless, such protection does not prevent an attacker from exploiting vulnerabilities at runtime. To detect such attacks, we propose an event-based behavior monitoring approach that relies on an isolated co-processor. We instrument the code executed on the main CPU to send information about its behavior to the monitor. This information helps to resolve the semantic gap issue. Our approach does not depend on a specific model of the behavior nor on a specific target. We apply this approach to detect attacks targeting the System Management Mode (SMM), a highly privileged x86 execution mode executing firmware code at runtime. We model the behavior of SMM using invariants of its control-flow and relevant CPU registers (CR3 and SMBASE). We instrument two open-source firmware implementations: EDKII and coreboot. We evaluate the ability of our approach to detect state-of-the-art attacks and its runtime execution overhead by simulating an x86 system coupled with an ARM Cortex A5 co-processor. The results show that our solution detects intrusions from the state of the art, without any false positives, while remaining acceptable in terms of performance overhead in the context of the SMM (i.e., less than the 150 us threshold defined by Intel).

The 911 emergency service belongs to one of the 16 critical infrastructure sectors in the United States. Distributed denial of service (DDoS) attacks launched from a mobile phone botnet pose a significant threat to the availability of this vital service. In this paper we show how attackers can exploit the cellular network protocols in order to launch an anonymized DDoS attack on 911. The current FCC regulations require that all emergency calls be immediately routed regardless of the caller's identifiers (e.g., IMSI and IMEI). A rootkit placed within the baseband firmware of a mobile phone can mask and randomize all cellular identifiers, causing the device to have no genuine identification within the cellular network. Such anonymized phones can issue repeated emergency calls that cannot be blocked by the network or the emergency call centers, technically or legally. We explore the 911 infrastructure and discuss why it is susceptible to this kind of attack. We then implement different forms of the attack and test our implementation on a small cellular network. Finally, we simulate and analyze anonymous attacks on a model of current 911 infrastructure in order to measure the severity of their impact. We found that with less than 6K bots (or \$100K hardware), attackers can block emergency services in an entire state (e.g., North Carolina) for days. We believe that this paper will assist the respective organizations, lawmakers, and security professionals in understanding the scope of this issue in order to prevent possible 911-DDoS attacks in the future.

Smart grid aims to improve control and monitoring routines to ensure reliable and efficient supply of electricity. The rapid advancements in information and communication technologies of Supervisory Control And Data Acquisition (SCADA) networks, however, have resulted in complex cyber physical systems. This added complexity has broadened the attack surface of power-related applications, amplifying their susceptibility to cyber threats. A particular class of system integrity attacks against the smart grid is False Data Injection (FDI). In a successful FDI attack, an adversary compromises the readings of grid sensors in such a way that errors introduced into estimates of state variables remain undetected. This paper presents an end-to-end case study of how to instantiate real FDI attacks to the Alternating Current (AC) –nonlinear– State Estimation (SE) process. The attack is realized through firmware modifications of the microprocessor-based remote terminal systems, falsifying the data transmitted to the SE routine, and proceeds regardless of perfect or imperfect knowledge of the current system state. The case study concludes with an investigation of an attack on the IEEE 14 bus system using load data from the New York Independent System Operator (NYISO).

Embedded devices are becoming more widespread, interconnected, and web-enabled than ever. However, recent studies showed that embedded devices are far from being secure. Moreover, many embedded systems rely on web interfaces for user interaction or administration. Web security is still difficult and therefore the web interfaces of embedded systems represent a considerable attack surface. In this paper, we present the first fully automated framework that applies dynamic firmware analysis techniques to achieve, in a scalable manner, automated vulnerability discovery within embedded firmware images. We apply our framework to study the security of embedded web interfaces running in Commercial Off-The-Shelf (COTS) embedded devices, such as routers, DSL/cable modems, VoIP phones, IP/CCTV cameras. We introduce a methodology and implement a scalable framework for discovery of vulnerabilities in embedded web interfaces regardless of the devices' vendor, type, or architecture. To reach this goal, we perform full system emulation to achieve the execution of firmware images in a software-only environment, i.e., without involving any physical embedded devices. Then, we automatically analyze the web interfaces within the firmware using both static and dynamic analysis tools. We also present some interesting case-studies and discuss the main challenges associated with the dynamic analysis of firmware images and their web interfaces and network services. The observations we make in this paper shed light on an important aspect of embedded devices which was not previously studied at a large scale.

Decreasing hardware reliability makes robust firmware imperative for safety-critical applications. Hence, ensuring correct handling of errors in peripherals is a key objective during firmware design. To adequately support robustness considerations of firmware designers during implementation, an efficient qualitative fault injection method is required. This paper presents a high-speed fault injection technique based on host-compiled firmware simulation that is suitable to analyze the impact of transient faults on firmware behavior. Additionally, fault set reduction by static code analysis avoids unnecessary injection of masked and equivalent faults. Application of the proposed fault injection technique on an industrial safety-relevant automotive system-on-chip (SoC) firmware demonstrates at least three orders of magnitude speedup compared to instruction set level. In addition, a fault set reduction by 78% is achieved. While significantly reducing the required fault injection time, the presented techniques provide as accurate feedback to the designer as existing state-of-the-art approaches.

Almost all commodity IT devices include firmware and software components from non-US suppliers, potentially introducing grave vulnerabilities to homeland security by enabling cyber-attacks via flaws injected into these devices through the supply chain. However, determining that a given device is free of any and all implementation flaws is computationally infeasible in the general case; hence a critical part of any vetting process is prioritizing what kinds of flaws are likely to enable potential adversary goals. We present Theseus, a four-year research project sponsored by the DARPA VET program. Theseus will provide technology to automatically map and explore the firmware/software (FW/SW) architecture of a commodity IT device and then generate attack scenarios for the device. From these device attack scenarios, Theseus then creates a prioritized checklist of FW/SW components to check for potential vulnerabilities. Theseus combines static program analysis, attack graph generation algorithms, and a Boolean satisfiability solver to automate the checklist generation workflow. We describe how Theseus exploits analogies between the commodity IT device problem and attack graph generation for networks. We also present a novel approach called Component Interaction Mapping to recover a formal model of a device's FW/SW architecture from which attack scenarios can be generated.

Basic Input Output System (BIOS) is the most important component of a computer system by virtue of its role i.e., it holds the code which is executed at the time of startup. It is considered as the trusted computing base, and its integrity is extremely important for smooth functioning of the system. On the contrary, BIOS of new computer systems (servers, laptops, desktops, network devices, and other embedded systems) can be easily upgraded using a flash or capsule mechanism which can add new vulnerabilities either through malicious code, or by accidental incidents, and deliberate attack. The recent attack on Iranian Nuclear Power Plant (Stuxnet) [1:2] is an example of advanced persistent attack. This attack vector adds a new dimension into the information security (IS) spectrum, which needs to be guarded by implementing a holistic approach employed at enterprise level. Malicious BIOS upgrades can also cause denial of service, stealing of information or addition of new backdoors which can be exploited by attackers for causing business loss, passive eaves dropping or total destruction of system without knowledge of user. To address this challenge a capability for verification of BIOS integrity needs to be developed and due diligence must be observed for proactive resolution of the issue. This paper explains the BIOS Integrity threats and presents a prevention strategy for effective and proactive resolution.