Rust is a promising programming language that focuses on concurrency, usability, and security. It is used in production code by major industry players and got recommended by government bodies. Rust provides strong security guarantees achieved by design utilizing the concepts of ownership and borrowing. However, Rust allows programmers to write unsafe code which is not subject to the strict Rust security policy. Empirical studies show that security issues in practice always involve code written in unsafe Rust.

Smart contracts are increasingly being used to manage large numbers of high-value cryptocurrency accounts. There is a strong demand for automated, efficient, and comprehensive methods to detect security vulnerabilities in a given contract. While the literature features a plethora of analysis methods for smart contracts, the existing proposals do not address the increasing complexity of contracts. Existing analysis tools suffer from false alarms and missed bugs in today’s smart contracts that are increasingly defined by complexity and interdependencies. To scale accurate analysis to modern smart contracts, we introduce EF↯CF, a high-performance fuzzer for Ethereum smart contracts. In contrast to previous work, EF↯CF efficiently and accurately models complex smart contract interactions, such as reentrancy and cross-contract interactions, at a very high fuzzing throughput rate. To achieve this, EF↯CF transpiles smart contract bytecode into native C++ code, thereby enabling the reuse of existing, optimized fuzzing toolchains. Furthermore, EF↯CF increases fuzzing efficiency by employing a structure-aware mutation engine for smart contract transaction sequences and using a contract’s ABI to generate valid transaction inputs. In a comprehensive evaluation, we show that EF↯CF scales better—without compromising accuracy—to complex contracts compared to state-of-the-art approaches, including other fuzzers, symbolic/concolic execution, and hybrid approaches. Moreover, we show that EF↯CF can automatically generate transaction sequences that exploit reentrancy bugs to steal Ether.

Return-oriented programming (ROP) is a powerful run-time exploitation technique to attack vulnerable software. Modern RISC architectures like RISC-V and ARM64 pose new challenges for ROP execution due to the lack of a stack-based return instruction and strict instruction alignment. Further, the large number of caller-saved argument registers significantly reduces the gadget space available to the attacker. Consequently, existing ROP gadget tools for other processor architectures cannot be applied to these RISC architectures. Previous work on RISC-V provides only manual construction of ROP attacks against specially crafted programs, and no analysis of ROP attacks has been conducted for ARM64 yet.