LAMBDA ENVIRONMENT VARIABLE SECURITY: INCIDENT INVESTIGATION, MASS CREDENTIAL ANALYSIS, AND ROTATION METHODOLOGY IN AWS CLOUD ENVIRONMENTS

Abstract

AWS Lambda is the dominant serverless compute platform, executing over one trillion function invocations per month across enterprise cloud environments. This paper investigates a critical, underexplored attack surface: plaintext credential exposure through the Lambda GetFunction API. When an attacker obtains high-privilege AWS credentials, every environment variable stored inline across all deployed Lambda functions becomes immediately accessible in a single automated sweep. This paper presents a forensic reconstruction of a real-world incident in which a compromised root access key enabled the exfiltration of credentials from ~1000 Lambda functions within 50 minutes. We describe a structured investigation methodology, present open-source tooling for mass credential classification, and propose a prioritised rotation and migration framework based on AWS Security Best Practices. Our findings demonstrate that environment variable storage in Lambda constitutes a systemic architectural vulnerability that requires organisational remediation beyond individual credential rotation.