Abstract

The application layer of the Open Systems Interconnection (OSI) model plays a critical role in enabling end-user interaction with network services, making it a primary target for cybersecurity threats. This paper reviews contemporary research on securing the application layer, addressing emerging threats such as injection attacks, malware, phishing, and zero-day vulnerabilities. Key strategies, including secure development practices, application firewalls, cryptographic protocols, and user education, are explored to mitigate these risks. The challenges of an evolving threat landscape and resource constraints are discussed, along with future directions leveraging artificial intelligence, blockchain, and zero trust architecture to enhance security. The findings underscore the importance of a multifaceted approach to safeguarding the application layer in an increasingly hostile cyber environment.