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→Bypassing Lock - Microchip/Atmel SAM4C32
==Bypassing Lock - Microchip/Atmel SAM4C32==
Hash Salehi
===Introduction===
When the security bit is bypassed the following commands can be run, shown with their associated output
==== at91sam4 info ====
> at91sam4 info
CKGR_MOR: [0x400e0420] -> 0x00000008
cpu-freq: 3.998 MHz
mclk-freq: 3.998 MHz
UniqueId: 0x20000c00 0x01006df3 0x010046af 0x010046b3<br ====reg==== > reg ===== arm v7m registers (0) r0 (/32): 0x00000000 (1) r1 (/32): 0x00000000 (2) r2 (/32): 0x00000000 (3) r3 (/32): 0x00000000 (4) r4 (/32): 0x00000000 (5) r5 (/32): 0x00000000 (6) r6 (/32): 0x00000000 (7) r7 (/32): 0x00000000 (8) r8 (/32): 0x00000000 (9) r9 (/32): 0x00000000 (10) r10 (/32): 0x00000000 (11) r11 (/32): 0x00000000 (12) r12 (/32): 0x00000000 (13) sp (/32): 0xffffffd8 (14) lr (/32): 0xfffffff9 (15) pc (/32): 0xfffffffe (16) xPSR (/32): 0x01000003 (17) msp (/32): 0xffffffd8 (18) psp (/32): 0x00000000 (20) primask (/1): 0x00 (21) basepri (/8): 0x00 (22) faultmask (/1): 0x00 (23) control (/3): 0x00 ===== Cortex-M DWT registers ====at91sam4 gpnvm====Note below GPNVM bit 0 says its current value is 0 due to the glitch, if the processor is reset we lose access and it goes back to 1. >at91sam4 gpnvm sam4-gpnvm0: 0 sam4-gpnvm1: 1 sam4-gpnvm2: 1
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===Other Vulnerable Devices===
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===Conclusion===