Ведущий: Маттео Беккаро (Matteo Beccaro) Доклад посвящен общим вопросам транспортной безопасности, мошенничества и технологических сбоев и будет интересен как профессиональным пентестерам, так и любителям. Докладчик рассмотрит несколько серьезных уязвимостей в реальных транспортных системах, в которых используется технология NFC, и продемонстрирует открытое приложение для тестирования таких систем со смартфона.

1. NFC
Naked Fried Chicken
Matteo Beccaro || Opposing Force
phdays 2016 – May 18, 2016
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2. Who ||
Matteo Beccaro
Founder || Chief Technology Officer at Opposing Force, the first
Italian company specialized in offensive physical security
Twitter: @_bughardy_
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3. Agenda ||
 NFC: What are we talking about?
 Transport system structure
 Our tool
 Pentesting methodology
 Attack Surface
 Analyzing the elements
 Vulnerabilities
 Case studies
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4. Agenda ||
 NFC: What are we talking about?
 Transport system structure
 Our tool
 Pentesting methodology
 Attack Surface
 Analyzing the elements
 Vulnerabilities
 Case studies
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5. NFC: What are we talking about?||
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What is NFC?
• NFC stands for Near Field Communication
• Frequency at 13.56 MHz
• 3-5 cm of range
• Widely used in:
– Access Control systems
– Ticketing
– Mobile phones

6. NFC: What are we talking about?||
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NFC most notorious families:
• MIFARE
– MIFARE Classic
– MIFARE Ultralight
– MIFARE DesFire
• HID iClass
• Calypso
• FeliCa

7. NFC: What are we talking about?||
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MIFARE Classic
• Memory storage device ( 1K or 4K )
• Strong access control mechanisms
– A key is required to access data sector
– Use of Crypto1 Crapto1 algorithm
– Broken…
– .. But widely used ( RFID Door token, transport ticket, etc )

8. NFC: What are we talking about?||
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MIFARE Ultralight
• Memory storage device ( 64 bytes )
• Basic security mechanism
– OTP ( One-Time-Programmable ) sector
– Lock bytes sector
– Mostly used for disposable tickets
– It has some more secure children:

9. NFC: What are we talking about?||
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MIFARE DesFire
• Advanced security mechanisms ( 3DES, AES, etc )
• File system structure
• 2KB, 4KB or 8KB memory size
• Several variant:
– DESFIRE, DESFIRE EV1 and DESFIRE EV2

10. NFC: What are we talking about?||
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HID iClass
• Same encryption and authentication keys are shared across
all HID iCLASS Standard Security installations.
• Keys are already been extracted
• Two variants:
– iClass Standard ( common )
– iClass High Secure ( less common )
Both broken

11. Agenda ||
 NFC: What are we talking about?
 Transport system structure
 Our tool
 Pentesting methodology
 Attack Surface
 Analyzing the elements
 Vulnerabilities
 Case studies
© Opposing Force. All right reserved.

12. Transport system structure||
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 Defining a transportation system:
 We need to create a common methodology
 We need to have tools
 We need to be able to use schemas to help our works

13. Transport system structure||
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 Defining a schema

14. Transport system structure||
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 Defining a schema
Local
Remot
e

15. Transport system structure||
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 More in details…

16. Transport system structure||
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 Token:
 Usually a NFC card
• MIFARE ULTRALIGHT
• MIFARE CLASSIC
• CALYPSO
 Can store:
• multiple rides or subscriptions
• timestamp of last stamping
• details of where it has been used
• other data

17. Transport system structure||
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 Token:
 MIFARE CLASSIC
• Just broken
 MIFARE ULTRALIGHT
• Lock attack
• Time attack
• Reply attack
 Calypso
• All documentation is under NDA

18. Transport system structure||
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 Reader|Controller:
 Can operate offline or online
 Can be wire or wireless connected to the controller
 Usually supports multiple standards
 Its purpose is to check if a ticket is valid and stamp it
 It can stores secrets and keys

19. Transport system structure||
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 Backend
 Sometimes known as “Cloud”
 It can perform several operations:
 Statistics
 OTA updates
 Fraud detection
 Fraud prevention

20. Agenda ||
 NFC: What are we talking about?
 Transport system structure
 Our tool(s)
 Pentesting methodology
 Attack Surface
 Analyzing the elements
 Vulnerabilities
 Case studies
© Opposing Force. All right reserved.

21. Our tool(s)||
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 What tools we can use:
 HydraNFC
 Proxmark3
 ChameleonMini
 NFCulT

22. Our tool(s)||
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HydraNFC ( ~ 90 € )
• Use Texas Instrument TRF7970A NFC chipset ( 13.56MHz only
)
• MIFARE 1k and 14443A UID emulation
• ISO 14443A sniffing ( also autonomous mode )
• 2 different raw modes
• Still in development ( @hydrabus )
• More info at http://hydrabus.com/hydranfc-1-0-
specifications/

23. Our tool(s)||
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Proxmark3 ( ~ 200 € )
• HF e LF capabilities
• Big community
• Supports almost all known RFID tags
• Supports sniffing
• Supports emulation
• More info at http://proxmark.org/forum/index.php

24. Our tool(s)||
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ChameleonMini ( ~ 100 € )
• HF ( 13.56MHz ) only
• Almost same capabilities of HydraNFC
• Different chipset
• Firmware available only for the old revision at the moment
• More info at http://kasper-oswald.de/gb/chameleonmini/

25. Our tool(s)||
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NFCulT ( ~ 0 € )
• Mobile application for NFC-enabled Android smartphones
• Its aim is to provide quick help during assessment of ticketing
systems
• Implements Lock, Time and Reply attacks
• It has a custom edit mode to edit bit by bit the ticket data
• Supports MIFARE ULTRALIGHT and planned support for
CLASSIC

26. Our tool(s)||
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NFCulT
• Lock Attack
• Set the OTP page in Read-Only mode
• Operation irreversible
• If the reader does not check if it can write
the OTP sector: free rides

27. Our tool(s)||
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NFCulT
• Time Attack
• If you find and decode the timestamp
you can stamp the ticket by yourself.
• Again, free rides

28. Our tool(s)||
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NFCulT
• Reply Attack
• Use of UID magic ticket ( ~ 15 € )
• Can bypass all offline anti fraud prevention
mechanisms
• Guess what? Free rides

29. Our tool(s)||
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NFCulT
• Custom edit
• Useful for understanding the architecture
of the data saved on the ticket ( e.g. for
finding the correct timestamp )
• You can quickly transform from hex to bin
and viceversa
• You can edit bit by bit the data and write
back on the ticket

30. Agenda ||
 NFC: What are we talking about?
 Transport system structure
 Our tool(s)
 Pentesting methodology
 Attack Surface
 Analyzing the elements
 Vulnerabilities
 Case studies
© Opposing Force. All right reserved.

31. Pentesting methodology||
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What are we looking for?

32. Pentesting methodology||
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Stamping machine
Attack Surface Attacks to Perform Impact
NFC Interface Analyze the stamping
mechanisms
Free tickets
Hardware board Analyze the exposed interface (
JTAG, UART, etc )
Firmware / secrets dumping
GSM/GPRS/Eth Interface Is MITM possible?
Intercepting the data
Intercepting secrets / sensitive
data

33. Pentesting methodology||
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Vending machine
Attack Surface Attacks to Perform Impact
NFC Interface Analyze the recharging
mechanisms
Free tickets, for everyone
Hardware board Analyze the exposed interface (
JTAG, UART, etc )
Firmware / secrets dumping
GSM/GPRS/Eth Interface Is MITM possible?
Intercepting the data
Intercepting secrets / sensitive
data
( e.g. credit card details, etc )
Computer Application Analyzing network services
exposed
Complete control of the machine

34. Pentesting methodology||
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The backend
Attack Surface Attacks to Perform Impact
Web application(s) Web app pentesting Various
Network services Network pentesting Various
Physical location Try to get physical access to the
servers
Pwned

35. Agenda ||
 NFC: What are we talking about?
 Transport system structure
 Our tool(s)
 Pentesting methodology
 Attack Surface
 Analyzing the elements
 Vulnerabilities
 Case studies
© Opposing Force. All right reserved.

36. Case studies ||
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A MIFARE ULTRALIGHT ticketing system

37. Case studies ||
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A MIFARE ULTRALIGHT ticketing system

38. Case studies ||
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A MIFARE ULTRALIGHT ticketing system
Lock bit for the OTP sector
is not checked by the
stamping machine
Absence of a UID blacklist
in the backend
Timestamp are not
encrypted nor signed

39. Case studies ||
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A MIFARE CLASSIC door lock

40. Case studies ||
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A MIFARE CLASSIC door lock

41. Case studies ||
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A MIFARE hotel door lock
Card’s UID
Room number:
int(0x17ea, 16) =
6122

42. ThanksOpposing Force - challenging your security - @_opposingforce
https://www.opposingforce.it | engage@opposingforce.it
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43. Q&A Time!Opposing Force - challenging your security - @_opposingforce
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