1. Enforcing Executing-Implies-Verified with the Integrity-Aware Processor Michael LeMay Carl A. Gunter University of Illinois at Urbana-Champaign Modified version of presentation for TRUST 2011

2. Motivation Contributions Design Conclusions and future work Outline 2

3. Injected malicious code into Programmable Logic Controller. – Can be blocked using code whitelisting. Stuxnet [Symantec Stuxnet Dossier 2011] 3 Clean OB1 Infected OB1

4. Corporate desktop PCs Chrome OS devices Advanced electric meters Power substation Intelligent Electronic Devices … Other Potential Applications 4

5. Existing approaches to malware detection and prevention exhibit limitations in the areas of: – Isolation – Visibility – Performance – Compatibility Motivation for Integrity-Aware Hardware 5

6. Motivation Contributions Design Conclusions and future work Outline 6

7. Integrity-Aware Processor: Only processor architecture with hardware support for directly detecting the execution of unverified code. XIVE kernel for IAP: Most compact integrity kernel that is capable of enforcing executing- implies-verified. Contributions 7

8. Motivation Contributions Design Conclusions and future work Outline 8

9. Hypervisors Operating System Hypervisor Hardware [SeshadriLQP2007-SOSP] 9 Integrity Kernel

10. Large Hypervisors Xen ~230 thousand lines of code Big attack surface! [LittyLL2008-Oakland] 10 Integrity Kernel

11. Hypervisor Vulnerabilities [IBM X-Force 2010] 11 (See chart on page 50 of the report cited below)

12. Integer overflow in the decompression loop memory allocator might result in overrunning the buffer used for the decompressed image. Integer overflows and lack of checking of certain length fields can result in the loader reading its own address space beyond the size of the supplied kernel image file. An attacker who can supply a kernel image to be booted as a paravirtualised guest might be able to: – Escalate privilege, taking control of the management domain and hence the entire machine. – Gain knowledge the contents of memory in the management tools. Depending on the toolstack in use this might contain sensitive information such as domain management or VNC passwords. Example: Xen security advisory CVE-2011-1583 (May 9, 2011) 12

13. System Management Mode APM Control Register Two orders of magnitude slowdown observed compared to protected mode. [AzabNWJZS2010-CCS] [WangSG2010-RAID] 13 Hardware Electrical Connection Integrity Kernel (sleeping dog picture by Eduardo Habkost via Flickr, CC BY 2.0)Flickr

14. Motivation Contributions Related work Design Conclusions and future work Outline 14

15. Integrity-Aware Processor 15 Based on LEON3 SPARCv8 (figure from paper)

16. IAP Complexities 16 (figure from paper)

17. Isolation: – IAP includes specific hardware support for isolating the integrity kernel, which is less complex than the MMU’s general protection mechanisms. Visibility: – IAP verification tracking mechanisms operate at TLB and cache level, removing page table walk mechanisms from TCB. IAP vs. MMU Hardware TCB 17

18. TCB Comparison XIVE contains 859 instructions 18

19. Hardware Prototype 19

20. Performance 20 (figure from paper)

21. Plentiful Dark Silicon Same area + same total heat dissipation + more transistors = lower % of simultaneously active transistors 37% slice overhead 21% BlockRAM overhead [SwansonT2011-IEEEComm] 21

22. Motivation Contributions Design Conclusions and future work Outline 22

23. Integrity-Aware Processor: Only processor architecture with hardware support for directly detecting the execution of unverified code. XIVE kernel for IAP: Most compact integrity kernel that is capable of enforcing executing- implies-verified. Contributions 23

24. Adapt IAP to other architectures. Explore integrity kernels for health information technology. Implement different types of policies within XIVE. Future Work 24

25. Hash vs. Network Overhead 25 (figure from paper)