In this paper, we propose Sequence-coverage Directed Fuzzing (SCDF), a lightweight directed fuzzing technique which explores towards the user-specified program statements efficiently. Given a set of target statement sequences of a program, SCDF aims to generate inputs that can reach the statements in each sequence in order and trigger bugs in the program. Moreover, we present a novel energy schedule algorithm, which adjusts on demand a seed's energy according to its ability of covering the given statement sequences calculated on demand. We implement the technique in a tool LOLLY in order to achieve efficiency both at instrumentation time and at runtime. Experiments on several real-world software projects demonstrate that LOLLY outperforms two well-established tools on efficiency and effectiveness, i.e., AFLGo-a directed greybox fuzzer and BugRedux-a directed symbolic-execution-based whitebox fuzzer.

In this paper, we propose and implement a generic, lightweight and extensible framework, LEOPARD, to identify potentially vulnerable functions through program metrics. LEOPARD requires no prior knowledge about known vulnerabilities. It has two steps by combining two sets of systematically derived metrics. First, it uses complexity metrics to group the functions in a target application into a set of bins. Then, it uses vulnerability metrics to rank the functions in each bin and identifies the top ones as potentially vulnerable. Our experimental results on 11 real-world projects have demonstrated that, LEOPARD can cover 74.0% of vulnerable functions by identifying 20% of functions as vulnerable and outperform machine learning-based and static analysis-based techniques. We further propose three applications of LEOPARD for manual code review and fuzzing, through which we discovered 22 new bugs in real applications like PHP, radare2 and FFmpeg, and eight of them are new vulnerabilities.

In this paper, we propose a deep-learning-based approach to predict the reachability of inputs (i.e., miss the target or not) before executing the target program, helping DGF filtering out the unreachable ones to boost the performance of fuzzing. To apply deep learning with DGF, we design a suite of new techniques (e.g., step-forwarding approach, representative data selection) to solve the problems of unbalanced labeled data and insufficient time in the training process. Further, we implement the proposed approach called FuzzGuard and equip it with the state-of-the-art DGF (e.g., AFLGo). Evaluations on 45 real vulnerabilities show that FuzzGuard boosts the fuzzing efficiency of the vanilla AFLGo up to 17.1×. Finally, to understand the key features learned by FuzzGuard, we illustrate their connection with the constraints in the programs

In this paper, we present sanitizer-guided fuzzing, a new design point in this space that specifically optimizes for bug coverage. For this purpose, we make the key observation that while the instrumentation performed by existing software sanitizers are regularly used for detecting fuzzer-induced error conditions, they can further serve as a generic and effective mechanism to identify interesting basic blocks for guiding fuzzers. We present the design and implementation of ParmeSan, a new sanitizer-guided fuzzer that builds on this observation. We show that ParmeSan greatly reduces the TTE of real-world bugs, and finds bugs 37% faster than existing state-of-the-art coverage-based fuzzers (Angora) and 288% faster than directed fuzzers (AFLGo), while still covering the same set of bugs.