Smart contracts powered by Blockchain render transaction processes more effective, secure and efficient when viewed alongside conventional contacts. Smart Contracts facilitate a trustworthy process and are characterized by time efficiency, cost-effectiveness and transparency, without any necessity for intervention by third-party intermediaries like lawyers. While Blockchains can counter, in a good way, traditional cyber-security attacks on Smart Contract Applications, cyber-criminals keep evolving new mechanisms of threats and attack vectors, capable of hacking Blockchain technologies. The research done in this chapter presents a unique framework to perform Application Security Testing on Blockchainbased Smart Contracts and also compares Manual Penetration Testing with two automated Smart Contract tools to identify critical vulnerabilities on the commercial scale in the Blockchain environment.