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Physical Security

Physical Security. Pieter.Harte@utwente.nl. Overview. Smart cards RFIDs Attacks (Semi)-Natural tags Conclusions. Smart Cards. Smart cards. Broken!. 53.98 mm. 85.6 mm. 0.76 mm.

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Physical Security

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  1. Physical Security Pieter.Harte@utwente.nl

  2. Overview • Smart cards • RFIDs • Attacks • (Semi)-Natural tags • Conclusions IIS

  3. Smart Cards

  4. Smart cards Broken! 53.98 mm 85.6 mm 0.76 mm [And96] R. J. Anderson and M. G. Kuhn. Tamper resistance - A cautionary note. In 2nd Int. Usenix Workshop on Electronic Commerce, pages 1-11, Oakland, California, Nov 1996. USENIX Association. http://www.usenix.org/publications/library/proceedings/ec96/kuhn.html IIS

  5. What makes the card smart? • CPU (8, 16, 32 bit) • Memory (RAM, ROM, EEPROM, Flash) • I/O channel (Contact/Contact less) • Cryptographic co-processor • On card devices (Fingerprint, display) • Standards (ISO 7816, GSM, EMV, VOP) IIS

  6. Main security features • Symmetric crypto • Asymmetric crypto relatively slow • Hardware random number generator • Hardware tamper resistance • X-tal clock vulnerable • Life cycle management IIS

  7. Communication • ISO 7816-4: 9600 bps : slow • USB : bulky • Bluetooth: power • Biometrics: slow www.fingerchip.com IIS

  8. Displays • Plastic, glass • Emissive, non-emissive • Refresh, bi-stable • Segment, dot-matrix • Problems: connections, yield, power, thickness, price! [Pra01] D. Praca and C. Barral. From smart cards to smart objects: the road to new smart technologies. Computer Networks, 36(4):381-389, Jul 2001. http://dx.doi.org/10.1016/S1389-1286(01)00161-X IIS

  9. Clock & Power • Clock • Xtal 0.6 mm • MEMS (0.002% acc.) • Battery • Thickness • power density • when to recharge IIS

  10. Integration is hard • Display • Button • 32-bit CPU • Large memory • Battery • Comms • >> 25mm2 Photo: Philips Semiconductors IIS

  11. RFID

  12. What is an RFID tag? • Antenna + small chip in ambient field • Passive, replies to queries only • Can be used for almost anything • Supply Chain Management & Checkout (Wallmart, Benetton) • Homeland security • User convenience • Access to buildings Nokia 6131 NFC IIS

  13. Passport application IIS

  14. Privacy issues • Sniffing • Data collection in proximity (skimming) • Correlate data from different tags • Counter measures • Shield antenna in passport with tinfoil • Encrypt the template with MRZ data • Reduce transmit range • Light controlled on/off switch • Long and short range interface • Time delayed transmit of sensitive info Watch this video [Bir07] N. Bird, C. Conrado, J. Guajardo, S. Maubach, G. Jan Schrijen, B. Skorić, A. M. H. Tombeur, P. Thueringer, and P. Tuyls. ALGSICS - combining physics and cryptography to enhance security and privacy in RFID systems. In F. Stajano, C. Meadows, S. Capkun, and T. Moore, editors, 4th European Workshop on Security and Privacy in Ad-hoc and Sensor Networks (ESAS), volume LNCS 4572, pages 187-202, Cambridge, UK, Jul 2007. Springer. http://dx.doi.org/10.1007/978-3-540-73275-4_14 IIS

  15. Attacks [Wit02] M. Witteman. Advances in smartcard security. Information Security Bulletin, pages 11-22, Jul 2002. http://www.riscure.com/fileadmin/images/Docs/ISB0707MW.pdf

  16. Attacks • Operational • Blackmail • Burglary • Bribery • Technical • Logical • Physical • Side channel • Attackers • I: Clever outsiders • II: Knowledgeable insiders • III: Funded Organisations IIS

  17. Logical attacks • The code is too complex • Hidden commands • Parameter poisoning & Buffer overflow • Malicious or buggy applets • Protocol problems (e.g. retransmit) • Proprietary crypto • Counter measures • Structured design & code inspection • Formal methods • Testing IIS

  18. Example: RFID virus • There is a large amount of code • Generic protocols and facilities • Back end data bases • So the usual attacks: • Buffer overflow • SQL injection “;shutdown--” • Don’t trust data from RFID tag… Best paper award [Rie06] M. R. Rieback, B. Crispo, and A. S. Tanenbaum. Is your cat infected with a computer virus? In 4th Annual IEEE Int. Conf. on Pervasive Computing and Communications (PerCom), pages 169-179, Pisa, Italy, Mar 2006. IEEE Computer Society. http://dx.doi.org/10.1109/PERCOM.2006.32 IIS

  19. Physical attacks • The circuitry is complex and vulnerable • Chemicals & etching • SEM Voltage contrast • Probe stations • Focused Ion Beam (FIB) to make probe pads • Counter measures • Reduced feature size (100nm) • Multi layering • Protective layers • Sensors • Bus scrambling IIS

  20. Low cost physical attacks • Block EEPROM writes by isolating Vpp • Rent focused Ion beam [And97d] R. J. Anderson and M. Kuhn. Low cost attacks on tamper resistant devices. In 5th Int. Workshop on Security Protocols, volume LNCS 1361, pages 125-136, Paris, France, Apr 1997. http://dx.doi.org/10.1007/BFb0028165 IIS

  21. Side channel attacks • Physical phenomena can be measured • Power • EM radiation (X-ray, light, sound) • Time • and changed • Voltage (example later) • Frequency (example later) Watch this video [Vua09] M. Vuagnoux and S. Pasini. Compromising electromagnetic emanations of wired andWireless keyboards. In 18th USENIX Security Symp., pages 1-16, Montreal, Canada, Aug 2009. USENIX Assoc. http://www.usenix.org/events/sec09/tech/full_papers/vuagnoux.pdf IIS

  22. Timing attack • Exponentiation by square and multiply • for i = n − 2 downto 0 • X = X2 • if (d[i] == 1) then • X = X*M • Power trace shows bits 1 in the key IIS

  23. Simple power analysis • 16 rounds DES • Rounds 2 & 3 [Koc99] P. C. Kocher, J. Jaffe, and B. Jun. Differential power analysis. In M. J. Wiener, editor, 19th Int. Conf. on Advances in Cryptology (CRYPTO), volume 1666 of LNCS, pages 388-397, Santa Barbara, California, Aug 1999. Springer. http://www.cryptography.com/resources/whitepapers/DPA.pdf IIS

  24. Differential power attacks • Difference in the third cycle due to difference in input value for encryption IIS

  25. Active attacks : Power Dip A power Dip at the Moment of reading a memory cell vcc • read a 0 as a 1 • Protection measure • Check VCC & raise an alarm if it drops • Problem: Fast transients during start-up may raise false alarms Reading threshold Stored value of logical zero gnd IIS

  26. Active attacks : Clock Glitch • Dump all of the memory • Replace 5MHz pulse by 4 pulses of 20MHz: • b = answer_address • a = answer_length • If (a == 0) goto 8 • transmit(*b) • b=b+1 • a=a-1 • goto 3 Glitch here [And97d] R. J. Anderson and M. Kuhn. Low cost attacks on tamper resistant devices. In 5th Int. Workshop on Security Protocols, volume LNCS 1361, pages 125-136, Paris, France, Apr 1997. http://dx.doi.org/10.1007/BFb0028165 IIS

  27. Countermeasures • Hardware • Lower power signals • Increase noise levels • Introduce timing noise • Software • Parallelism • Introduce random delays • Constant time execution • Blinding intermediate values IIS

  28. Countermeasures • Make attacks harder but not impossible • Hard to get right • Expensive to implement IIS

  29. Out of the box thinking • The humble Capacitor • Emanates acoustic signals • Sensitive to shocks and vibration • C  A / d IIS

  30. Listen to a PC multiplying Freeze 1500 μF capacitor http://people.csail.mit.edu/tromer/acoustic/ IIS

  31. Shaking a smart card.... IIS

  32. Attackers business case Rental! IIS

  33. Design guidelines • Define the level of security needed • Perform a risk analysis • Consider the attackers business case • Use the right technologies • Build in fraud management • Design recovery and fall-back • Consider the overall system IIS

  34. IBM 4758 Crypto Coprocessor • Rolls Royce of secure devices • Tamper sensing barrier • Keys move in the RAM • Temperature & X-ray sensor • Solid aluminium case & epoxy potting • low pass filter on power supply • Used in ATMs • Hacked! [Cla03b] R. Clayton and M. Bond. Experience using a Low-Cost FPGA design to crack DES keys. In 4th Int. Workshop on Cryptographic Hardware and Embedded Systems (CHES), volume LNCS 2523, pages 877-883, Redwood Shores, California, 2003. Springer. http://dx.doi.org/10.1007/3-540-36400-5_42 IIS

  35. (Semi) Natural tags

  36. Finger printing [Buc05] J. D. R. Buchanan, R. P. Cowburn, A.-V. Jausovec, D. Petit, P. Seem, G. Xiong, D. Atkinson, K. Fenton, D. A. Allwood, and M. T. Bryan. Forgery: 'fingerprinting' documents and packaging. Nature, 436(7050):475, Jul 2005. http://dx.doi.org/10.1038/436475a IIS

  37. Philips Coating PUF [Sko08] B. Škorić, G.-J. Schrijen, W. Ophey, R. Wolters, N. Verhaegh, and J. van Geloven. Experimental hardware for coating PUFs and optical PUFs. In P. Tuyls, B. Škorić, and T. Kevenaar, editors, Security with Noisy Data - On Private Biometrics, Secure Key Storage and Anti-Counterfeiting, pages 255-268. Springer London, 2008. http://dx.doi.org/10.1007/978-1-84628-984-2_15 IIS

  38. MEMS particles • 1x1x12 m particles, shapes • Church and school roof, power line grease/gel • Jewellery fluid • Spray vandals/thiefs • Smart water Watch this video [Kay92] P. H. Kaye, F. Micheli, M. Tracey, E. Hirst, and A. M. Gundlach. The production of precision silicon micromachined non-spherical particles for aerosol studies. Journal of Aerosol Science, 23(Suppl 1):201-204, 1992. http://dx.doi.org/10.1016/0021-8502(92)90384-8 http://www.redwebsecurity.com/ IIS

  39. Conclusions • Affordable tamper resistance technology exists • Getting it right is difficult • Out of the box thinking required IIS

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