Techniques to Protect Confidentiality and Integrity of Persistant and In-Memory Data

to protect this data against confidentiality and integrity violations that can result
in the illicit release, loss, or modification of a user’s and an organization’s sensitive
data such as personal media content or client records. Existing techniques protecting
confidentiality and integrity lack either efficiency or are vulnerable to malicious
attacks. In this thesis we suggest techniques, Guardat and ERIM, to efficiently and
robustly protect persistent and in-memory data.

To protect the confidentiality and integrity of persistent data, clients specify
per-file policies to Guardat declaratively, concisely and separately from code. Guardat
enforces policies by mediating I/O in the storage layer. In contrast to prior techniques,
we protect against accidental or malicious circumvention of higher software layers.
We present the design and prototype implementation, and demonstrate that Guardat
efficiently enforces example policies in a web server.

To protect the confidentiality and integrity of in-memory data, ERIM isolates
sensitive data using Intel Memory Protection Keys (MPK), a recent x86 extension
to partition the address space. However, MPK does not protect against malicious
attacks by itself. We prevent malicious attacks by combining MPK with call gates
to trusted entry points and ahead-of-time binary inspection. In contrast to existing
techniques, ERIM efficiently protects frequently-used session keys of web servers,
an in-memory reference monitor’s private state, and managed runtimes from native
libraries. These use cases result in high switch rates of the order of 10 5 –10 6 switches/s.
Our experiments demonstrate less then 1% runtime overhead per 100,000 switches/s,
thus outperforming existing techniques.