Serverless applications, particularly those deployed on AWS Lambda, are vulnerable to security threats due to their reliance on external dependencies such as libraries and frameworks. These dependencies can contain known vulnerabilities that are not patched by the cloud provider, making them a target for attackers. To mitigate this risk, developers should use tools like Snyk to scan their dependencies for vulnerabilities and automatically remediate issues before deployment. Additionally, integrating security testing into the development lifecycle, such as using plugins in integrated development environments (IDEs), can help identify vulnerabilities early on. It is also essential to enforce secure deployments by subjecting the function's deployment workflow to security review and ceasing deployments when vulnerabilities are found. By taking these steps, developers can protect their serverless applications from security threats and ensure a more secure development lifecycle.