SANS CyberCast - SANS@Mic -Attacking Serverless Servers: Reverse Engineering the AWS, Azure, and GCP Function Runtimes

  • Webcast Aired Wednesday, 25 Mar 2020 8:30PM EDT (26 Mar 2020 00:30 UTC)
  • Speaker: Brandon Evans

The cloud makes it easy for developers to launch their applications, integrate with managed services, and think little about the underlying infrastructure. Unfortunately, this can and has come back to bite us. Last year's Capital One breach has made security professionals all too aware of the internal details of AWS, such as the EC2 Instance Metadata Service, which allowed a malicious actor to steal credentials for an IAM role that enabled them to pilfer documents from countless S3 buckets. The serverless ecosystem is no different. In order to give our functions access to the cloud services they need, the cloud provider needs to provide them with the necessary credentials. If a function's runtime is owned, so are these credentials. This presentation will explain how a compromised serverless function can be used to exfiltrate sensitive data, persist malware, gain powerful credentials, and pivot to other cloud services. It will contain live demonstrations of creating and exploiting reverse shell connections for AWS Lambda, Azure Functions, and Google Cloud Functions. These malicious functions and associated research have been published on GitHub by Brandon Evans and Eric Johnson under a repository called \Serverless Prey" (https://github.com/pumasecurity/serverless-prey).