FwAnalyzer is a tool to analyze (ext2/3/4), FAT/VFat, SquashFS, UBIFS filesystem images, cpio archives, and directory content using a set of configurable rules. FwAnalyzer relies on e2tools for ext filesystems, mtools for FAT filesystems, squashfs-tools for SquashFS filesystems, and ubi_reader for UBIFS filesystems. cpio for cpio archives. SELinux/Capability support for ext2/3/4 images requires a patched version of e2tools. SELinux/Capability support for SquashFS images requires a patched version of squashfs-tools. The main idea of FwAnalyzer is to provide a tool for rapid analysis of filesystem images as part of a firmware security Q&A check suite. FwAnalyzer takes a configuration file that defines various rules for files and directories and runs the configured checks against a given filesystem image. The output of FwAnalyzer is a report, which contains the list of files that violate any of the rules specified in the configuration. The report further contains meta information about the filesystem image and, if configured, information extracted from files within the analyzed filesystem. The report is formatted using JSON so it can be easily integrated as a step in a larger analysis.