Download Enhancing Non-determinism in Operating Systems A Thesis

2.7 Camouflage ..............................................................................................................16
3. Gold-Standard Refresh...................................................................................................18
3.1 Hypervisor Design ...................................................................................................22
3.2 Goal 1: Diskless, Read-only Bootstrapping .............................................................23
3.2.1 The MBR Bootloader ........................................................................................25
3.2.2 The Stage-1 Bootloader ....................................................................................26
3.2.3 The Stage-2 Bootloader ....................................................................................27
3.2.4 PXE Boot ..........................................................................................................28
3.3 Goal 2: Kernel Refresh, Denying Persistence..........................................................29
3.3.1 Enabling Virtualization .....................................................................................29
3.3.2 The Hypervisor Main Loop ..............................................................................30
3.3.3 Kernel Environment ..........................................................................................32
3.4 Goal 3: MULTICS-style Protections Applied to Kernels ........................................34
3.5 Goal 4: Processor State Protection ...........................................................................38
3.6 Attack Surface Minimization ...................................................................................40
3.7 Supporting Legacy Operating Systems ....................................................................41
3.8 Summary ..................................................................................................................42
4. Diversity through Compile-Time Techniques ...............................................................43
4.1 Implementation ........................................................................................................44
4.1.1 The Padding Transformation ............................................................................44
4.1.2 The Ordering Transformation ...........................................................................46
4.2 Quantifying Diversity ..............................................................................................47
4.2.1 Entropy of the Padding Transformation ...........................................................48
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