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#1 19921127  Icon User is offline

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Phase 5 - Binary Bomb

Posted 18 October 2017 - 12:50 PM

Hello there, I have just begun learning about assembly and I came across this fun project called Binary Bomb which seemed like a fun exercise. Binary Bomb has 6 phases, for each phase you need to read assembly code in order to obtain a password that will allow to move to the next phase without exploding the bomb. I have completed the first 4 phases of the bomb but phase 5 has left me incredibly confused. I can't seem to figure out how to solve it. So far, I believe the input needs to be a string of 6 chars, but I can't seem to figure out where to go from there. I feel like there's something crucial I'm missing. Any tips or hints that could potentially help me would be much appreciated. Thanks!

Dump of assembler code for function phase_5:
=> 0x0000000000401105 <+0>:	push   %rbx
   0x0000000000401106 <+1>:	mov    %rdi,%rbx
   0x0000000000401109 <+4>:	callq  0x40135a <string_length>
   0x000000000040110e <+9>:	cmp    $0x6,%eax
   0x0000000000401111 <+12>:	je     0x401118 <phase_5+19>
   0x0000000000401113 <+14>:	callq  0x40164c <explode_bomb>
   0x0000000000401118 <+19>:	mov    %rbx,%rax
   0x000000000040111b <+22>:	lea    0x6(%rbx),%rdi
   0x000000000040111f <+26>:	mov    $0x0,%ecx
   0x0000000000401124 <+31>:	movzbl (%rax),%edx
   0x0000000000401127 <+34>:	and    $0xf,%edx
   0x000000000040112a <+37>:	add    0x4026c0(,%rdx,4),%ecx
   0x0000000000401131 <+44>:	add    $0x1,%rax
   0x0000000000401135 <+48>:	cmp    %rdi,%rax
   0x0000000000401138 <+51>:	jne    0x401124 <phase_5+31>
   0x000000000040113a <+53>:	cmp    $0x2d,%ecx
   0x000000000040113d <+56>:	je     0x401144 <phase_5+63>
   0x000000000040113f <+58>:	callq  0x40164c <explode_bomb>
   0x0000000000401144 <+63>:	pop    %rbx
   0x0000000000401145 <+64>:	retq 


(gdb) x/16dw 0x4026c0
0x4026c0 <array.3601>: 2 10 6 1
0x4026d0 <array.3601+16>: 12 16 9 3
0x4026e0 <array.3601+32>: 4 7 14 5
0x4026f0 <array.3601+48>: 11 8 15 13

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Replies To: Phase 5 - Binary Bomb

#2 modi123_1  Icon User is online

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Re: Phase 5 - Binary Bomb

Posted 18 October 2017 - 12:56 PM

Are you sure you copied that homework right?

Example:
http://www.dreaminco...nary-bomb-help/
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#3 19921127  Icon User is offline

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Re: Phase 5 - Binary Bomb

Posted 18 October 2017 - 01:00 PM

View Postmodi123_1, on 18 October 2017 - 12:56 PM, said:

Are you sure you copied that homework right?

Example:
http://www.dreaminco...nary-bomb-help/


Sorry, but what do you mean by that? Copied?
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#4 modi123_1  Icon User is online

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Re: Phase 5 - Binary Bomb

Posted 18 October 2017 - 01:02 PM

Seems like a common homework assignment. Are you are certain you have all the required lines of code to walk through?
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#5 19921127  Icon User is offline

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Re: Phase 5 - Binary Bomb

Posted 18 October 2017 - 01:12 PM

Yes, I think so? I believe the bomb phases are randomized depending on what "version" of the bomb you happen to download. This is what I've got for my Phase 5.
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