Software reverse engineering education

Software Reverse Engineering (SRE) is the practice of analyzing a software system, either in whole or in part, to extract design and implementation information. A typical SRE scenario would involve a software module that has worked for years and carries several rules of a business in its lines of code. Unfortunately the source code of the application has been lost; what remains is “native ” or “binary ” code. Reverse engineering skills are also used to detect and neutralize viruses and malware as well as to protect intellectual property. It became frighteningly apparent during the Y2K crisis that reverse engineering skills were not commonly held amongst programmers. Since that time, much research has been undertaken to formalize the types of activities that fall into the category of reverse engineering so that these skills can be taught to computer programmers and testers. To help address the lack of software reverse engineering education, several peer-reviewed articles on software reverse engineering, re-engineering, reuse, maintenance, evolution, and security were gathered with the objective of developing relevant, practical exercises for instructional purposes. The research revealed that SRE is fairly well described and most of the related activities fall into one of tw

Decompiler For Pseudo Code Generation

Decompiling is an area of interest for researchers in the field of software reverse engineering. When the source code from a high-level programming language is compiled, it loses a great deal of information, including code structure, syntax, and punctuation.The purpose of this research is to develop an algorithm that can efficiently decompile assembly language into pseudo C code. There are tools available that claim to extract high-level code from an executable file, but the results of these tools tend to be inaccurate and unreadable.Our proposed algorithm can decompile assembly code to recover many basic high-level programming structures, including if/else, loops, switches, and math instructions. The approach adopted here is different from that of existing tools. Our algorithm performs three passes through the assembly code, and includes a virtual execution of each assembly instruction. We also construct a dependency graph and incidence list to aid in the decompilation

Looking for Criminal Intents in JavaScript Obfuscated Code

The majority of websites incorporate JavaScript for client-side execution in a supposedly protected environment. Unfortunately, JavaScript has also proven to be a critical attack vector for both independent and state-sponsored groups of hackers. On the one hand, defenders need to analyze scripts to ensure that no threat is delivered and to respond to potential security incidents. On the other, attackers aim to obfuscate the source code in order to disorient the defenders or even to make code analysis practically impossible. Since code obfuscation may also be adopted by companies for legitimate intellectual-property protection, a dilemma remains on whether a script is harmless or malignant, if not criminal. To help analysts deal with such a dilemma, a methodology is proposed, called JACOB, which is based on five steps, namely: (1) source code parsing, (2) control flow graph recovery, (3) region identification, (4) code structuring, and (5) partial evaluation. These steps implement a sort of decompilation for control flow flattened code, which is progressively transformed into something that is close to the original JavaScript source, thereby making eventual code analysis possible. Most relevantly, JACOB has been successfully applied to uncover unwanted user tracking and fingerprinting in e-commerce websites operated by a well-known Chinese company

Get rid of inline assembly through verification-oriented lifting

Formal methods for software development have made great strides in the last two decades, to the point that their application in safety-critical embedded software is an undeniable success. Their extension to non-critical software is one of the notable forthcoming challenges. For example, C programmers regularly use inline assembly for low-level optimizations and system primitives. This usually results in driving state-of-the-art formal analyzers developed for C ineffective. We thus propose TInA, an automated, generic, trustable and verification-oriented lifting technique turning inline assembly into semantically equivalent C code, in order to take advantage of existing C analyzers. Extensive experiments on real-world C code with inline assembly (including GMP and ffmpeg) show the feasibility and benefits of TInA

Generic Reverse Compilation to Recognize Specific Behavior

Práce je zaměřena na rozpoznávání specifického chování pomocí generického zpětného překladu. Generický zpětný překlad je proces, který transformuje spustitelné soubory z různých architektur a formátů objektových souborů na stejný jazyk na vysoké úrovni. Tento proces se vztahuje k nástroji Lissom Decompiler. Pro účely rozpoznání chování práce zavádí Language for Decompilation -- LfD. LfD představuje jednoduchý imperativní jazyk, který je vhodný pro srovnávaní. Konkrétní chování je dáno známým spustitelným souborem (např. malware) a rozpoznání se provádí jako najítí poměru podobnosti s jiným neznámým spustitelným souborem. Tento poměr podobnosti je vypočítán nástrojem LfDComparator, který zpracovává dva vstupy v LfD a rozhoduje o jejich podobnosti.Thesis is aimed on recognition of specific behavior by generic reverse compilation. The generic reverse compilation is a process that transforms executables from different architectures and object file formats to same high level language. This process is covered by a tool Lissom Decompiler. For purpose of behavior recognition the thesis introduces Language for Decompilation -- LfD. LfD represents a simple imperative language, which is suitable for a comparison. The specific behavior is given by the known executable (e.g. malware) and the recognition is performed as finding the ratio of similarity with other unknown executable. This ratio of similarity is calculated by a tool LfDComparator, which processes two sources in LfD to decide their similarity.

On Matching Binary to Source Code

Reverse engineering of executable binary programs has diverse applications in computer security and forensics, and often involves identifying parts of code that are reused from third party software projects. Identification of code clones by comparing and fingerprinting low-level binaries has been explored in various pieces of work as an effective approach for accelerating the reverse engineering process. Binary clone detection across different environments and computing platforms bears significant challenges, and reasoning about sequences of low-level machine in- structions is a tedious and time consuming process. Because of these reasons, the ability of matching reused functions to their source code is highly advantageous, de- spite being rarely explored to date. In this thesis, we systematically assess the feasibility of automatic binary to source matching to aid the reverse engineering process. We highlight the challenges, elab- orate on the shortcomings of existing proposals, and design a new approach that is targeted at addressing the challenges while delivering more extensive and detailed results in a fully automated fashion. By evaluating our approach, we show that it is generally capable of uniquely matching over 50% of reused functions in a binary to their source code in a source database with over 500,000 functions, while narrowing down over 75% of reused functions to at most five candidates in most cases. Finally, we investigate and discuss the limitations and provide directions for future work

SmartInspect: Smart Contract Inspection Technical Report

Smart contracts are embedded procedures stored with the data they act upon. Debugging deployed Smart Contracts is a difficult task since once deployed, the code cannot be reexecuted and inspecting a simple attribute is not easily possible because data is encoded. In this technical report, we present SmartInspect to address the lack of inspectability of a deployed contract. Our solution analyses the contract state by using decompilation techniques and a mirror-based architecture to represent the object responsible for interpreting the contract state. SmartInspect allows developers and also end-users of a contract to better visualize and understand the contract stored state without needing to redeploy, nor develop any ad-hoc code