Open data gathering and how to use it in cybersecurity

This thesis deals with Data Gathering from Open Sources which can be used in Cyber Security; an analysis of the OSINT tools; a creation of a Data Gathering Tool itself. The theoretical part of the thesis explores Data Gathering within the framework of Ethical Hacking and in which phase of Penetration Testing the Data Extraction is crucial. Following the analysis of the OSINT tools the Practical part of the thesis examines the Created Tool itself which was written in Python programming language. Via API interface the Tool allows interaction with other OSINT tools such as Censys, crt.sh or DNSDumpster. After entering the IP address or domain of the target company the Tool is able to search for basic information such as location, DNS names and running services. Based on the target URL the Tool is able to show both present and absent HTTP security headers on the given website and also based on the entered domain it can search for SSL/TLS certificates, subdomains and emails of the target company