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s c a l e Marc Witteman Croatian Summer school 2017 Attack - PowerPoint PPT Presentation

Jul 28, 2023 β€’429 likes β€’688 views

When Hardware Attacks s c a l e Marc Witteman Croatian Summer school 2017 Attack exploitation space: time vs distance Remote key brute software protocol force relay attack side Fast Slow mitm channel Hardware attacks require:

  1. When Hardware Attacks s c a l e Marc Witteman Croatian Summer school 2017

  2. Attack exploitation space: time vs distance Remote key brute software protocol force relay attack side Fast Slow mitm channel Hardware attacks require: Hardware attacks β€’ hardware vulnerabilities, or fault β€’ hardware changes to target injection physical 2 Local

  3. Attacker business case π‘ž = π‘œ βˆ— 𝑀 βˆ’ 𝑑 𝑀 βˆ’ 𝑑 𝑔 p = profit v = value n = replications c v = variable costs c f = fixed costs 3

  4. Let’s analyze some known attacks 1. EMV Man-in-the-Middle Hardware attack to bypass PIN verification of stolen payment cards 2. Retail hack Network penetration attack to retrieve cardholder credentials 3. Card sharing Relay attack to avoid paying TV subscription fees 4

  5. EMV Man-in-the-Middle (1) 5 Source: https://www.cl.cam.ac.uk/research/security/banking/nopin/

  6. EMV Man-in-the-Middle (2) 6

  7. Retail hack 7

  8. Card sharing (1) β€’ Pay-TV decoders use smart cards to control video access β€’ Subscription is in smart card 8

  9. Card sharing (2) β€’ Pay-TV decoders use smart cards to control video access β€’ Subscription is in smart card β€’ Distribution of session keys avoids need for individual subscriptions 9

  10. Example attack business cases Attack Fixed Variable Value Replications Profit Cost Cost € 30K € 100 € 500 100 € 10 K EMV MitM € 20K € 1 € 25 € 220 K Retail hack 10K € 10K € 10 € 100 1M € 90 M Card sharing Replications are key, but how is that bounded? β€’ Application size (e.g. #potential victims) β€’ Replication effort β€’ Detection & mitigation Hardware attacks require substantial replication effort Can they be scalable? 10

  11. Attack phases Identification Exploitation What it is finding a vulnerability run on target Frequency once repeated Speed slow fast Skill expert script-kiddy Equipment expensive cheap Location local remote Scalable attacks need software exploitation! Scalable attack

  12. How to find software vulnerabilities? Black-Box White-Box Model Based Binary Source Code Fuzzing Testing Analysis Review Attackers method Defenders method Effectiveness Most vulnerabilities are found white-box style! 12

  13. Finding vulnerabilities in source code Software packages typically vary between 10 and 10,000 KLoC have 0.1 up to 10 vulnerabilities per KLoC οƒ  All products have software vulnerabilities Manual source code review performs at 100 LoC/hr οƒ  Finding a vulnerability in source code may take just one day 13

  14. Binary analysis

  15. Firmware structure analysis Key block packed loader boot loader packed main application

  16. Disassemble

  17. Flow analysis

  18. Design flaw in Pay-TV SoC Source: http://www.fredericb.info/2016/10/amlogic-s905-soc-bypassing-not-so.html

  19. Secure boot chain broken by backdoor Attacker used Public sources Boot Loader image Restricted 19

  20. Boot Loader header analysis struct aml_img_header { // 64 bytes unsigned char magic[4];// "@AML" Analysis & experimenting showed that uint32_t total_len; sig_type selects different key lengths, or none! uint8_t header_len; uint8_t unk_x9; Code Certificate Signature uint8_t unk_xA; uint8_t unk_xB; uint32_t unk_xC; Hash Verify Get key uint32_t sig_type; uint32_t sig_offset; uint32_t sig_size; Hashed code Public key Verified Sig uint32_t data_offset; uint32_t unk_x20; uint32_t cert_offset; Select uint32_t cert_size; uint32_t data_len; Compare uint32_t unk_x30; uint32_t code_offset; uint32_t code_len; Stop Go uint32_t unk_x3C; } aml_img_header_t; 20

  21. Recent hack on WI-FI chip Source: https://googleprojectzero.blogspot.fr/2017/04/over-air-exploiting-broadcoms-wi-fi_4.html

  22. Stack buffer overflow in WI-FI SoC enables remote code execution within WI-FI range Complex multi-step attack Used public utility to do memory dump! Leveraged information from other chips Affects both iOS and Android devices 22

  23. Reducing risk with encrypted software Binary analysis Exploitation Start exposes logical yields runtime vulnerability control Encrypted software hides binary code Exploitation Start Black-Box penetration testing yields runtime exposes logical vulnerability control Black-Box penetration testing very inefficient Hardware attack Binary analysis Exploitation Start breaks software exposes logical yields runtime confidentiality control vulnerability Hardware attack offers two-step alternative: 1. Break software confidentiality 23 2. White-box binary analysis exposes logical vulnerability

  24. Conclusions Scalable attacks need software exploitation o Hardware attacks are laborious o Software vulnerabilities are ubiquitous o Software exploits are easy to reproduce Software encryption is inevitable for security o Binary analysis very successful in identifying vulnerabilities o Increasing number of products use encrypted software Hardware attacks are scalable when o Software is encrypted o Shallow bugs (detectable black-box style) are absent o Used in the identification step to extract software o Deep software vulnerabilities are present 24

  25. Marc Witteman Contact: witteman@riscure.com Riscure is hiring, visit https://www.riscure.com/careers/ Riscure B.V. Riscure North America Frontier Building, Delftechpark 49 550 Kearny St. 2628 XJ Delft Suite 330 The Netherlands San Francisco, CA 94108 Phone: +31 15 251 40 90 +1 (650) 646 9979 www.riscure.com inforequest@riscure.com

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