Software maintenance and reuse require identification of the applied software licenses. The information needs of maintainers and reusers can be supported by reverse engineering tools at different information retrieval levels. The paper presents a reverse engineering approach called ASLA for retrieving license information typically used in OSS. User needs, system architecture, tool features, and tool evaluation are presented. The implemented tool features include support for identifying source file dependencies and licenses in source files. The tool is evaluated against another tool for license information extraction. ASLA supports the same programming languages as GCC. License identification coverage is good and the tool is extendable.