Biblio

The spread of the Internet of Things (IoT) and the use of smart control systems in many mission-critical or safety-critical applications domains, like automotive or aeronautical, make devices attractive targets for attackers. Nowadays, several of these are mixed-criticality systems, i.e., they run both high-criticality tasks (e.g., a car control system) and low-criticality ones (e.g., infotainment). High-criticality routines often employ Real-Time Operating Systems (RTOS) to enforce hard real-time requirements, while the tasks with lower constraints can be delegated to more generic-purpose operating systems (GPOS).Much of the control code for these devices is written in memory-unsafe languages such as C and C++. This makes them susceptible to powerful binary attacks, such as the famous Return-Oriented Programming (ROP). Control-Flow Integrity (CFI) is the most investigated security technique to protect against such threats. At now, CFI solutions for real-time embedded systems are not as mature as the ones for general-purpose systems, and even more, there is a lack of in-depth studies on how different operating systems with different security requirements and timing constraints can coexist on a single multicore platform.This paper aims at drawing attention to the subject, discussing the current scientific proposal, and in turn proposing a solution for an optimized asymmetric verification system for execution integrity. By using an embedded hypervisor, predefined cores could be dedicated to only high or low-criticality tasks, with the high-priority core being monitored by the lower-criticality core, relying on offline binary instrumentation and a light exchange of information and signals at runtime. The work also presents preliminary results about a possible implementation for multicore ARM platforms, running both RTOS and GPOS, both in terms of security and performance penalties.

This paper shows that the modern high customizable Xtensa architecture for embedded devices is exploitable by Return-Oriented Programming (ROP) attacks. We used a simple Hello-World application written with the RIOT OS as an almost minimal code basis for determining if the number of gadgets that can be found in this code base is sufficient to build a reasonably complex attack. We determined 859 found gadgets which are sufficient to create a gadget catalog for the Xtensa. Despite the code basis used being really small, the presented gadget catalog provides Turing completeness, which allows an arbitrary computation of any exploit program.

Control flow integrity (CFI) checks are used in desktop systems, in order to protect them from various forms of attacks, but they are rarely investigated for embedded systems, due to their introduced overhead. The contribution of this paper is an efficient software implementation of a CFI-check for ARM-and Xtensa processors. Moreover, we propose the combination of this CFI-check with another defense mechanism against return-oriented-programming (ROP). We show that by this combination the security is significantly improved. Moreover, it will also in-crease the safety of the system, since the combination can detect a failed ROP-attack and bring the system in a safe state, which is not possible when using each technique separately. We will also report on the introduced overhead in code size and run time.

The problem of buffer overflow in the information system is not threatening, and the system's own defense mechanism can detect and terminate code injection attacks. However, as countermeasures compete with each other, advanced stack overflow attacks have emerged: Return Oriented-Programming (ROP) technology, which has become a hot spot in the field of system security research in recent years. First, this article explains the reason for the existence of this technology and the attack principle. Secondly, it systematically expounds the realization of the return-oriented programming technology at home and abroad in recent years from the common architecture platform, the research of attack load construction, and the research of variants based on ROP attacks. Finally, we summarize the paper.

Nowadays, exploits often rely on a code-reuse approach. Short pieces of code called gadgets are chained together to execute some payload. Code-reuse attacks can exploit vul-nerabilities in the presence of operating system protection that prohibits data memory execution. The ROP chain construction task is the code generation for the virtual machine defined by an exploited executable. It is crucial to understand how powerful ROP attacks can be. Such knowledge can be used to improve software security. We implement MAJORCA that generates ROP and JOP payloads in an architecture agnostic manner and thoroughly consider restricted symbols such as null bytes that terminate data copying via strcpy. The paper covers the whole code-reuse payloads construction pipeline: cataloging gadgets, chaining them in DAG, scheduling, linearizing to the ready-to-run payload. MAJORCA automatically generates both ROP and JOP payloads for x86 and MIPS. MAJORCA constructs payloads respecting restricted symbols both in gadget addresses and data. We evaluate MAJORCA performance and accuracy with rop-benchmark and compare it with open-source compilers. We show that MAJORCA outperforms open-source tools. We propose a ROP chaining metric and use it to estimate the probabilities of successful ROP chaining for different operating systems with MAJORCA as well as other ROP compilers to show that ROP chaining is still feasible. This metric can estimate the efficiency of OS defences.

Return-oriented programming(ROP) is a prevalent technique that targets return addresses to hijack control flow. To prevent such attack, researchers mainly focus on either Shadow Stack or MAC-based mechanisms(message code authentication). But Shadow Stack suffers from additional memory overhead and information leakage, while MAC-based mechanisms(e.g. Zipper Stack) impose high runtime overhead for MAC calculations.In this paper, we propose Twine Stack, a hybrid and efficient return address protection mechanism with lightweight hardware extension. It utilizes a tiny hardware shadow stack to realize a new multi-chain Zipper Stack. Specifically, each entry in the shadow stack stores a return address and its MAC in each chain, allowing queueing calculation with just one hash module. At meantime, some return address verifications could be done by comparison with the hardware shadow stack, instead of calculation again. We implemented Twine Stack on RISC-V architecture, and evaluated it on FPGA board. Our experiments show that Twine Stack reduces over 95% hash verifications, and imposes merely 1.38% performance overhead with an area overhead of 974 LUTs and 726 flip flops. The result demonstrates that our hybrid scheme mitigates the drawbacks of each separate scheme.

Code-reuse attacks pose a threat to embedded devices since they are able to defeat common security defenses such as non-executable stacks. To succeed in his code-reuse attack, the attacker has to gain knowledge of some or all of the instructions of the target firmware/software. In case of a bare-metal firmware that is protected from being dumped out of a device, it is hard to know the running instructions of the target firmware. This consequently makes code-reuse attacks more difficult to achieve. This paper shows how an attacker can gain knowledge of some of these instructions by sniffing the unencrypted incremental updates. These updates exist to reduce the radio reception power for resource-constrained devices. Based on the literature, these updates are checked against authentication and integrity, but they are sometimes sent unencrypted. Therefore, it will be demonstrated how a Return-Oriented Programming (ROP) attack can be accomplished using only the passively sniffed incremental updates. The generated updates of the R3diff and Delta Generator (DG) differencing algorithms will be under assessment. The evaluation reveals that both of them can be exploited by the attacker. It also shows that the DG generated updates leak more information than the R3diff generated updates. To defend against this attack, different countermeasures that consider different power consumption scenarios are proposed, but yet to be evaluated.

Return-oriented programming (ROP) is an effective code-reuse attack in which short code sequences (i.e., gadgets) ending in a ret instruction are found within existing binaries and then executed by taking control of the call stack. The shadow stack, control flow integrity (CFI) and code (re)randomization are three popular techniques for protecting programs against return address overwrites. However, existing runtime rerandomization techniques operate on concrete return addresses, requiring expensive pointer tracking. By adding one level of indirection, we introduce BarRA, the first shadow stack mechanism that applies continuous runtime rerandomization to abstract return addresses for protecting their corresponding concrete return addresses (protected also by CFI), thus avoiding expensive pointer tracking. As a nice side-effect, BarRA naturally combines the shadow stack, CFI and runtime rerandomization in the same framework. The key novelty of BarRA, however, is that once some abstract return addresses are leaked, BarRA will enforce the burn-after-reading property by rerandomizing the mapping from the abstract to the concrete return address space in the order of microseconds instead of seconds required for rerandomizing a concrete return address space. As a result, BarRA can be used as a superior replacement for the shadow stack, as demonstrated by comparing both using the 19 C/C++ benchmarks in SPEC CPU2006 (totalling 2,047,447 LOC) and analyzing a proof-of-concept attack, provided that we can tolerate some slight binary code size increases (by an average of 29.44%) and are willing to use 8MB of dedicated memory for holding up to 220 return addresses (on a 64-bit platform). Under an information leakage attack (for some return addresses), the shadow stack is always vulnerable but BarRA is significantly more resilient (by reducing an attacker's success rate to [1/(220)] on average). In terms of the average performance overhead introduced, both are comparable: 6.09% (BarRA) vs. 5.38% (the shadow stack).

Memory corruption vulnerabilities, mainly present in C and C++ applications, may enable attackers to maliciously take control over the program running on a target machine by forcing it to execute an unintended sequence of instructions present in memory. This is the principle of modern Code-Reuse Attacks (CRAs) and of famous attack paradigms as Return-Oriented Programming (ROP) and Jump-Oriented Programming (JOP). Control-Flow Integrity (CFI) is a promising approach to protect against such runtime attacks. Recently, many CFI-based solutions have been proposed, resorting to both hardware and software implementations. However, many of these solutions are hardly applicable to microcontroller systems, often very resource-limited. The paper presents a generic, portable, and lightweight CFI solution for bare-metal embedded systems, i.e., systems that execute firmware directly from their Flash memory, without any Operating System. The proposed defense mixes software and hardware instrumentation and is based on monitoring the Control-Flow Graph (CFG) with an FPGA connected to the CPU. The solution, applicable in principle to any architecture which disposes of an FPGA, forces all control-flow transfers to be compliant with the CFG, and preserves the execution context from possible corruption when entering unpredictable code such as Interrupt Services Routines (ISR).

The impact of microarchitectural attacks in Personal Computers (PCs) can be further adapted to and observed in internetworked All Programmable System-on-Chip (AP SoC) platforms. This effort involves the access control or execution of Intellectual Property cores in the FPGA of an AP SoC Victim internetworked with an AP SoC Attacker via Internet Protocol (IP). Three conceptions of attacks were implemented: buffer overflow attack at the stack, return-oriented programming attack, and command-injection-based attack for dynamic reconfiguration in the FPGA. Indeed, a specific preventive countermeasure for each attack is proposed. The functionality of the countermeasures mainly comprises adapted words addition (stack protection) for the first and second attacks and multiple encryption for the third attack. In conclusion, the recommended countermeasures are realizable to counteract the implemented attacks.

Runtime memory vulnerabilities, especially present in widely used languages as C and C++, are exploited by attackers to corrupt code pointers and hijack the execution flow of a program running on a target system to force it to behave abnormally. This is the principle of modern Code Reuse Attacks (CRAs) and of famous attack paradigms as Return-Oriented Programming (ROP) and Jump-Oriented Programming (JOP), which have defeated the previous defenses against malicious code injection such as Data Execution Prevention (DEP). Control-Flow Integrity (CFI) is a promising approach to protect against such runtime attacks. Recently, many CFI solutions have been proposed, with both hardware and software implementations. But how can a defense based on complying with a graph calculated a priori efficiently deal with something unpredictable as exceptions and interrupt requests? The present paper focuses on this dichotomy by analysing some of the CFI-based defenses and showing how the unexpected trigger of an interrupt and the sudden execution of an Interrupt Service Routine (ISR) can circumvent them.

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.

Exploits based on ROP (Return-Oriented Programming) are increasingly present in advanced attack scenarios. Testing systems for ROP-based attacks can be valuable for improving the security and reliability of software. In this paper, we propose ROPMATE, the first Visual Analytics system specifically designed to assist human red team ROP exploit builders. In contrast, previous ROP tools typically require users to inspect a puzzle of hundreds or thousands of lines of textual information, making it a daunting task. ROPMATE presents builders with a clear interface of well-defined and semantically meaningful gadgets, i.e., fragments of code already present in the binary application that can be chained to form fully-functional exploits. The system supports incrementally building exploits by suggesting gadget candidates filtered according to constraints on preserved registers and accessed memory. Several visual aids are offered to identify suitable gadgets and assemble them into semantically correct chains. We report on a preliminary user study that shows how ROPMATE can assist users in building ROP chains.

Despite decades of research on software diversification, only address space layout randomization has seen widespread adoption. Code randomization, an effective defense against return-oriented programming exploits, has remained an academic exercise mainly due to i) the lack of a transparent and streamlined deployment model that does not disrupt existing software distribution norms, and ii) the inherent incompatibility of program variants with error reporting, whitelisting, patching, and other operations that rely on code uniformity. In this work we present compiler-assisted code randomization (CCR), a hybrid approach that relies on compiler-rewriter cooperation to enable fast and robust fine-grained code randomization on end-user systems, while maintaining compatibility with existing software distribution models. The main concept behind CCR is to augment binaries with a minimal set of transformation-assisting metadata, which i) facilitate rapid fine-grained code transformation at installation or load time, and ii) form the basis for reversing any applied code transformation when needed, to maintain compatibility with existing mechanisms that rely on referencing the original code. We have implemented a prototype of this approach by extending the LLVM compiler toolchain, and developing a simple binary rewriter that leverages the embedded metadata to generate randomized variants using basic block reordering. The results of our experimental evaluation demonstrate the feasibility and practicality of CCR, as on average it incurs a modest file size increase of 11.46% and a negligible runtime overhead of 0.28%, while it is compatible with link-time optimization and control flow integrity.

Control-hijacking attacks include code injection attacks and code reuse attacks. In recent years, with the emergence of the defense mechanism data-execution prevention(DEP), code reuse attacks have become mainstream, such as return-oriented programming(ROP), Jump-Oriented Programming(JOP), and Counterfeit Object-oriented Programming(COOP). And a series of defensive measures have been proposed, such as DEP, address space layout randomization (ASLR), coarse-grained Control-Flow Integrity(CFI) and fine-grained CFI. In this paper, we propose a new attack called function-oriented programming(FOP) to construct malicious program behavior. FOP takes advantage of the existing function of the C program to induce attack. We propose concrete algorithms for FOP gadgets and build a tool to identify FOP gadgets. FOP can successfully bypass coarse-grained CFI, and FOP also can bypass some existing fine-grained CFI technologies, such as shadow stack technology. We show a real-world attack for proftpd1.3.0 server in the Linux x64 environment. We believe that the FOP attack will encourage people to come up with more effective defense measures.

Memory-based vulnerabilities are a major source of attack vectors. They allow attackers to gain unauthorized access to computers and their data. Previous research has made significant progress in detecting attacks. However, developers still need to locate and fix these vulnerabilities, a mostly manual and time-consuming process. They face a number of challenges. Particularly, the manifestation of an attack does not always coincide with the exploited vulnerabilities, and many attacks are hard to reproduce in the lab environment, leaving developers with limited information to locate them. In this paper, we propose Ravel, an architectural approach to pinpoint vulnerabilities from attacks. Ravel consists of an online attack detector and an offline vulnerability locator linked by a record & replay mechanism. Specifically, Ravel records the execution of a production system and simultaneously monitors it for attacks. If an attack is detected, the execution is replayed to reveal the targeted vulnerabilities by analyzing the program's memory access patterns under attack. We have built a prototype of Ravel based on the open-source FreeBSD operating system. The evaluation results in security and performance demonstrate that Ravel can effectively pinpoint various types of memory vulnerabilities and has low performance overhead.

Memory corruption errors in C/C++ programs remain the most common source of security vulnerabilities in today’s systems. Control-flow hijacking attacks exploit memory corruption vulnerabilities to divert program execution away from the intended control flow. Researchers have spent more than a decade studying and refining defenses based on Control-Flow Integrity (CFI); this technique is now integrated into several production compilers. However, so far, no study has systematically compared the various proposed CFI mechanisms nor is there any protocol on how to compare such mechanisms. We compare a broad range of CFI mechanisms using a unified nomenclature based on (i) a qualitative discussion of the conceptual security guarantees, (ii) a quantitative security evaluation, and (iii) an empirical evaluation of their performance in the same test environment. For each mechanism, we evaluate (i) protected types of control-flow transfers and (ii) precision of the protection for forward and backward edges. For open-source, compiler-based implementations, we also evaluate (iii) generated equivalence classes and target sets and (iv) runtime performance.

Memory corruption errors in C/C++ programs remain the most common source of security vulnerabilities in today's systems. Over the last 10+ years the security community developed several defenses [4]. Data Execution Prevention (DEP) protects against code injection – eradicating this attack vector. Yet, control-flow hijacking and code reuse remain challenging despite wide deployment of Address Space Layout Randomization (ASLR) and stack canaries. These defenses are probabilistic and rely on information hiding. The deployed defenses complicate attacks, yet control-flow hijack attacks (redirecting execution to a location that would not be reached in a benign execution) are still prevalent. Attacks reuse existing gadgets (short sequences of code), often leveraging information disclosures to learn the location of the desired gadgets. Strong defense mechanisms have not yet been widely deployed due to (i) the time it takes to roll out a security mechanism, (ii) incompatibility with specific features, and (iii) performance overhead. In the meantime, only a set of low-overhead but incomplete mitigations has been deployed in practice. Control-Flow Integrity (CFI) [1,2] and Code-Pointer Integrity (CPI) [3] are two promising upcoming defense mechanisms, protecting against control-flow hijacking. CFI guarantees that the runtime control flow follows the statically determined control-flow graph. An attacker may reuse any of the valid transitions at any control-flow transfer. We compare a broad range of CFI mechanisms using a unified nomenclature based on (i) a qualitative discussion of the conceptual security guarantees, (ii) a quantitative security evaluation, and (iii)\textbackslashtextasciitildean empirical evaluation of their performance in the same test environment. For each mechanism, we evaluate (i) protected types of control-flow transfers, (ii) the precision of the protection for forward and backward edges. For open-source compiler-based implementations, we additionally evaluate (iii) the generated equivalence classes and target sets, and (iv) the runtime performance. CPI on the other hand is a dynamic property that enforces selective memory safety through bounds checks for code pointers by separating code pointers from regular data.

In 2007, Shacham published a seminal paper on Return-Oriented Programming (ROP), the first systematic formulation of code reuse. The paper has been highly influential, profoundly shaping the way we still think about code reuse today: an attacker analyzes the "geometry" of victim binary code to locate gadgets and chains these to craft an exploit. This model has spurred much research, with a rapid progression of increasingly sophisticated code reuse attacks and defenses over time. After ten years, the common perception is that state-of-the-art code reuse defenses are effective in significantly raising the bar and making attacks exceedingly hard. In this paper, we challenge this perception and show that an attacker going beyond "geometry" (static analysis) and considering the "dynamics" (dynamic analysis) of a victim program can easily find function call gadgets even in the presence of state-of-the-art code-reuse defenses. To support our claims, we present Newton, a run-time gadget-discovery framework based on constraint-driven dynamic taint analysis. Newton can model a broad range of defenses by mapping their properties into simple, stackable, reusable constraints, and automatically generate gadgets that comply with these constraints. Using Newton, we systematically map and compare state-of-the-art defenses, demonstrating that even simple interactions with popular server programs are adequate for finding gadgets for all state-of-the-art code-reuse defenses. We conclude with an nginx case study, which shows that a Newton-enabled attacker can craft attacks which comply with the restrictions of advanced defenses, such as CPI and context-sensitive CFI.

The kernel code injection is a common behavior of kernel-compromising attacks where the attackers aim to gain their goals by manipulating an OS kernel. Several security mechanisms have been proposed to mitigate such threats, but they all suffer from non-negligible performance overhead. This article introduces a hardware reference monitor, called Kargos, which can detect the kernel code injection attacks with nearly zero performance cost. Kargos monitors the behaviors of an OS kernel from outside the CPU through the standard bus interconnect and debug interface available with most major microprocessors. By watching the execution traces and memory access events in the monitored target system, Kargos uncovers attempts to execute malicious code with the kernel privilege. On top of this, we also applied the architectural supports for Kargos to the detection of ROP attacks. KS-Stack is the hardware component that builds and maintains the shadow stacks using the existing supports to detect this ROP attacks. According to our experiments, Kargos detected all the kernel code injection attacks that we tested, yet just increasing the computational loads on the target CPU by less than 1% on average. The performance overhead of the KS-Stack was also less than 1%.

Return-oriented programming (ROP) has been crucial for attackers to evade the security mechanisms of operating systems. It is currently used in malicious documents that exploit viewer applications and cause malware infection. For inspecting a large number of commonly handled documents, high-performance and flexible-detection methods are required. However, current solutions are either time-consuming or less precise. In this paper, we propose a novel method for statically detecting ROP chains in malicious documents. Our method generates a hidden Markov model (HMM) of ROP chains as well as one of benign documents by learning known malicious and benign documents and libraries used for ROP gadgets. Detection is performed by calculating the likelihood ratio between malicious and benign HMMs. In addition, we reduce the number of false positives by ROP chain integrity checking, which confirms whether ROP gadgets link properly if they are executed. Experimental results showed that our method can detect ROP-based malicious documents with no false negatives and few false positives at high throughput.

Code diversification is an effective mitigation against return-oriented programming attacks, which breaks the assumptions of attackers about the location and structure of useful instruction sequences, known as "gadgets". Although a wide range of code diversification techniques of varying levels of granularity exist, most of them rely on the availability of source code, debug symbols, or the assumption of fully precise code disassembly, limiting their practical applicability for the protection of closed-source third-party applications. In-place code randomization has been proposed as an alternative binary-compatible diversification technique that is tolerant of partial disassembly coverage, in the expense though of leaving some gadgets intact, at the disposal of attackers. Consequently, the possibility of constructing robust ROP payloads using only the remaining non-randomized gadgets is still open. In this paper we present instruction displacement, a code diversification technique based on static binary instrumentation that does not rely on complete code disassembly coverage. Instruction displacement aims to improve the randomization coverage and entropy of existing binary-level code diversification techniques by displacing any remaining non-randomized gadgets to random locations. The results of our experimental evaluation demonstrate that instruction displacement reduces the number of non-randomized gadgets in the extracted code regions from 15.04% for standalone in-place code randomization, to 2.77% for the combination of both techniques. At the same time, the additional indirection introduced due to displacement incurs a negligible runtime overhead of 0.36% on average for the SPEC CPU2006 benchmarks.

Heterogeneous Chip Multiprocessors have been shown to provide significant performance and energy efficiency gains over homogeneous designs. Recent research has expanded the dimensions of heterogeneity to include diverse Instruction Set Architectures, called Heterogeneous-ISA Chip Multiprocessors. This work leverages such an architecture to realize substantial new security benefits, and in particular, to thwart Return-Oriented Programming. This paper proposes a novel security defense called HIPStR – Heterogeneous-ISA Program State Relocation – that performs dynamic randomization of run-time program state, both within and across ISAs. This technique outperforms the state-of-the-art just-in-time code reuse (JIT-ROP) defense by an average of 15.6%, while simultaneously providing greater security guarantees against classic return-into-libc, ROP, JOP, brute force, JIT-ROP, and several evasive variants.