Amass is an open-source tool developed by OWASP that performs comprehensive attack surface mapping and asset discovery for organizations and security professionals. The tool focuses on identifying and enumerating external assets associated with target domains through various reconnaissance techniques. It utilizes multiple data sources including DNS records, certificate transparency logs, web archives, and search engines to discover subdomains, IP addresses, and other network infrastructure components. Amass provides several operational modes including passive information gathering that relies on public data sources without directly interacting with target systems, and active reconnaissance that performs direct queries and scans. The tool can map relationships between discovered assets and visualize the attack surface through network graphs. The platform supports integration with various APIs and data sources to enhance discovery capabilities. It includes features for DNS enumeration, subdomain discovery, certificate analysis, and ASN mapping. Results can be exported in multiple formats for further analysis and integration with other security tools. Amass is designed to help security teams understand their external attack surface by identifying potentially unknown or forgotten assets that could present security risks.