Application security is the practice of protecting software and its data throughout design, development, deployment, and maintenance. It covers applications such as web and mobile services, APIs, and the libraries and cloud configurations they depend on. Typical weaknesses include injection, broken access controls, insecure authentication, exposed secrets, unsafe deserialization, and vulnerable third-party components.
These flaws can let an attacker read or alter data, impersonate users, execute unauthorized actions, or gain a foothold in connected systems. Effective defenses include threat modeling and secure coding, peer review, automated testing, dependency and secret scanning, timely vulnerability remediation, and penetration testing for higher-risk functions. Controls must continue after release: logging and application-layer monitoring can help detect abuse, while well-tested access controls, safe configuration, and an incident-response plan limit and investigate exploitation. Vulnerability management should prioritize issues by exploitability, exposure, affected data, and the privileges available through the application.