Command-line options (e.g., -l , -F , -R for ls ) given to a command-line program can significantly alternate the behaviors of the program. Thus, fuzzing not only file input but also program options can improve test coverage and bug detection. In this article, we propose ZigZagFuzz which achieves higher test coverage and detects more bugs than the state-of-the-art fuzzers by separately mutating program options and file inputs in an iterative/interleaving manner. ZigZagFuzz applies the following three core ideas. First, to utilize different characteristics of the program option domain and the file input domain, ZigZagFuzz separates phases of mutating program options from ones of mutating file inputs and performs two distinct mutation strategies on the two different domains. Second, to reach deep segments of a target program that are accessed through an interleaving sequence of program option checks and file inputs checks, ZigZagFuzz continuously interleaves phases of mutating program options with phases of mutating file inputs. Finally, to improve fuzzing performance further, ZigZagFuzz periodically shrinks input corpus by removing similar test inputs based on their function coverage. The experiment results on the 20 real-world programs show that ZigZagFuzz improves test coverage and detects 1.9 to 10.6 times more bugs than the state-of-the-art fuzzers that mutate program options such as AFL++-argv, AFL++-all, Eclipser, CarpetFuzz, ConfigFuzz, and POWER. We have reported the new bugs detected by ZigZagFuzz, and the original developers confirmed our bug reports.

Most programs with command-line interface (CLI) have dozens of command-line options (e.g., -l, -F, -R for ls) to alternate the operation of the programs. Thus, depending on the option configurations (i.e., a list of options like -l -F and -F -R) applied during fuzzing, the test coverage and crash detection results can vary significantly. In this paper, we propose a novel fuzzing technique POWER that detects more crashes than the cutting-edge fuzzers by actively constructing and carefully selecting various program option configurations. The salient idea of POWER is to enforce diverse executions of a target program by selecting a set of the option configurations each of which is far “different/distant” from the others in the set. Another core idea of POWER is to apply different fuzzing strategies to different input domains (i.e., option configurations and input files) to increase testing effectiveness within limited time budget. The experiment results on the 30 real-world programs show that POWER detects significantly more crash bugs than the state-of-the-art fuzzing techniques.