Fav-up

fav-up is an open source reconnaissance utility designed to identify servers and websites by analyzing favicon hashes and querying the Shodan search engine. It calculates the hash of a favicon image and then uses that value to search Shodan for other hosts that use the same icon. This technique is commonly used in security research and OSINT investigations to discover related infrastructure or services that may belong to the same organization. fav-up can retrieve favicon data from several sources, including local files, direct favicon URLs, or full web pages where the favicon is automatically extracted. fav-up then computes the favicon hash and performs Shodan queries to locate IP addresses that match the same hash. To support larger investigations, the tool can iterate over lists of URLs, domains, or favicon files in bulk. Results can be printed to the console or exported into structured formats such as CSV or JSON for further analysis and reporting.