Adversaries in Clouds: Protecting Data in Cloud-Based Applications Nick Feamster Georgia Tech

Building Applications on the Cloud Used for a wide variety of services and applications Built using a variety of technology – Programming languages – Web servers – Load balancers – Application frameworks New opportunities for external adversaries – About 85% of data leaks occur due to external attacks at servers [Verizon data breach report]. – Existing attacks on software applications – But, applications are also hosted on untrusted platforms “You can’t trust code that you did not totally create yourself.” – Ken Thomson, Reflections on Trusting Trust

Possible Defenses Check the Web application for vulnerabilities – Doesn’t defend against zero-day attacks, programmer error, etc. – Must trust all underlying hardware and software infrastructure, as well – No protection once the account is compromised Isolate each session in a virtual machine – Significant performance overhead

Protect the Data (in addition to the application) Proposal: A data firewall for cloud-based Web applications Apply network-level information flow control to data hosted by Web applications – Associate a taint with a piece of data (e.g., row in a database table) – Rewrite queries to retrieve taints with data – Propagate taints across processes and network – Perform IFC based on taints associated with data

New Adversary Models The “foreign” code base is increasing – Application security is getting harder Position: Protect the data, not just the application Network-wide DLP could benefit cloud-based applications in other settings, too – Data isolation between multi-tenant application services