Serverless computing abstracts away infrastructure management. Developers focus on code, and the cloud provider handles everything else. This convenience creates security blind spots unique to serverless architectures.
Function permissions often grant excessive access. Developers assign broad IAM roles to Lambda functions or Azure Functions, granting access to every S3 bucket or database rather than only necessary resources. Compromised functions leverage these excessive permissions.
Secrets management becomes complex in serverless environments. Functions need database credentials, API keys, and other sensitive information. Hardcoding secrets in function code or environment variables creates obvious vulnerabilities. Proper secrets management requires additional services and careful configuration.
Serverless functions execute untrusted input. User data flows into functions through API gateways, message queues, and event triggers. Input validation failures in serverless code enable injection attacks, just like traditional applications. Comprehensive AWS penetration testing examines serverless function security alongside traditional infrastructure.
Cold start vulnerabilities create race conditions. Functions inactive for some time require cold starts, increasing latency. Attackers exploit timing differences between cold and warm starts, sometimes extracting secrets or causing unexpected behaviour during initialisation.
William Fieldhouse, Director of Aardwolf Security Ltd, explains: “Serverless security challenges stem from distributed architectures and shared responsibility models. Developers must secure their code and configurations while trusting the cloud provider for infrastructure security. Getting this boundary right requires understanding both application and cloud security.”
Dependency vulnerabilities affect serverless functions like any other application. Functions package dependencies with their code. Outdated libraries with known vulnerabilities create exploitable weaknesses. Dependency scanning needs integration into serverless deployment pipelines.
Logging and monitoring require deliberate configuration. Serverless functions execute briefly and disappear. Without proper logging configuration, understanding function behaviour or investigating incidents becomes impossible. Centralised logging aggregates output from numerous function invocations.
Denial of service through resource exhaustion works differently in serverless. Attackers trigger massive numbers of function invocations, generating enormous cloud bills. Rate limiting, reserved concurrency, and budget alerts help control costs and prevent abuse.
Lateral movement between functions leverages excessive permissions and shared resources. Compromised functions that can invoke other functions or access shared databases enable attackers to traverse your serverless architecture systematically.
API Gateway security controls the front door to serverless applications. Proper authentication, rate limiting, and input validation at the gateway prevent many attacks from reaching functions.Azure penetration testing evaluates serverless security across your entire cloud architecture.
Infrastructure as code security matters enormously. Serverless deployments rely heavily on IaC templates. Misconfigurations in CloudFormation, Terraform, or ARM templates deploy vulnerable functions at scale. IaC security scanning catches issues before deployment.
