ARM Crackme - Data Processing
@Wunkolo and I have decided that there aren’t enough ARM crackmes on the forum and that we should add a few for people that are interested in learning how the architecture works and for those that just want to show their skills 
We will start very easy with some challenges that don’t require any kind of setup or reading up specific processor manuals but that will change when the challenges get harder.
This challenge will most likely be the last one to contain formated extracted assembly so if you prefer trying it out through dynamic analysis as a warm up a binary is provided as well.
Rules and Goals
In this challenge the goal is to deduct the original password from the assembly/binary.
Post it in spoiler tags under the challenge if you got it so we can see who solved it!
Challenge
After seeing how easy the last password has been recovered I thought that this might be not ideal to secure all my data that way.
Which is why I’ve written this new super secure program that doesn’t sole base on exclusive and processes the password in multiple ways!
Although I’m pretty confident in my new method I would like you to confirm that it’s not possible to recover the secret password anymore.
Dump of the relevant assembly
08460 main STMFD SP!, {R11,LR}
08464 ADD R11, SP, #4
08468 LDR R3, =var_8638 ; "%s"
0846C MOV R0, R3
08470 LDR R1, =input
08474 BL __isoc99_scanf
08478 LDR R0, =input
0847C BL strlen
08480 MOV R3, R0
08484 CMP R3, #0x14
08488 BEQ loc_8494
0848C MOV R3, #1
08490 B loc_8570
08494 loc_8494 LDR R3, =input_10798
08498 LDR R2, [R3]
0849C LDR R3, =0x12345678
084A0 EOR R3, R2, R3
084A4 LDR R2, =0x69790439
084A8 LDR R2, [R2]
084AC CMP R3, R2
084B0 BEQ loc_84BC
084B4 MOV R3, #1
084B8 B loc_8570
084BC loc_84BC LDR R3, =input_1079C
084C0 LDR R2, [R3]
084C4 LDR R3, =input
084C8 LDR R3, [R3]
084CC ADD R2, R2, R3
084D0 LDR R3, =0xC2819E87
084D4 CMP R2, R3
084D8 BEQ loc_84E4
084DC MOV R3, #1
084E0 B loc_8570
084E4 loc_84E4 LDR R3, =input_107A0
084E8 LDR R2, [R3]
084EC LDR R3, =input_1079C
084F0 LDR R3, [R3]
084F4 RSB R2, R3, R2
084F8 LDR R3, =0xE91E0419
084FC CMP R2, R3
08500 BEQ loc_850C
08504 MOV R3, #1
08508 B loc_8570
0850C loc_850C LDR R3, =input_107A0
08510 LDR R2, [R3]
08514 LDR R3, =input_107A4
08518 LDR R3, [R3]
0851C RSB R2, R3, R2
08520 LDR R3, =0xDD1F1D1C
08524 CMP R2, R3
08528 BEQ loc_8534
0852C MOV R3, #1
08530 B loc_8570
08534 loc_8534 LDR R3, =input_107A8
08538 LDR R2, [R3]
0853C LDR R3, =input_107A4
08540 LDR R3, [R3]
08544 ADD R2, R2, R3
08548 LDR R3, =0xD07A8174
0854C CMP R2, R3
08550 BEQ loc_855C
08554 MOV R3, #1
08558 B loc_8570
0855C loc_855C LDR R3, =aCorrectTheFlag ; "Correct! The flag is: %s\n"
08560 MOV R0, R3
08564 LDR R1, =input
08568 BL printf
0856C MOV R3, #0
08570 loc_8570 MOV R0, R3
08574 SUB SP, R11, #4
08578 LDMFD SP!, {R11,LR}
0857C BX LR
(Optional) Binary in base64 format
Extract with:
cat base64below.txt | base64 -d | gunzip > binary.elf
File type:
ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.26, not stripped
Base64 encoded gzip archive: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As these challenges are meant for learning this section will contain some resources to look into that will help solving this challenge.