lab2 - BE A Hacker Fudan University Parallel Processing...

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Unformatted text preview: BE A Hacker Fudan University Parallel Processing Institute Rong Chen Dr. Evil mailto: SS10 from Dr. Evil The nefarious Dr. Evil has planted a slew of binary bombs on our machines. A binary BOMB is a program that consists of a sequence of phases. Each phase expects you to type a PASSWORD on stdin. If you type the correct string, then the phase is defused and the bomb proceeds to the next phase. Otherwise, the bomb explodes by printing " BOOM!!! " and then terminating. The bomb is defused when every phase has been defused. Chance ! WANTED HACKE R Defuse Bomb What is Bomb ? Only a binary file What should you do ? Find the key and defuse the bomb ! What can you use ? Anything from ICS course Any tools Right key Survive Wrong key Bomb ! gdb strings calculator pencil paper objdump Demo Please See Carefully ! A binary bomb Need a password to defuse it Demo $./example input password: bomb!... $ $./example input password: survive! 224 123 Step by Step Machine Code to Assembly Code objdump-D example > asm NAME objdump- display information from object files. SYNOPSIS objdump [-d|--disassemble] [-D|--disassemble-all] ... 080483c4 <main>: ... 80483d5: c7 04 24 38 85 04 08 movl $0x8048538,(%esp) 80483dc: e8 17 ff ff ff call 80482f8 <printf@plt> 80483e1: 8d 45 f8 lea 0xfffffff8(%ebp),%eax 80483e4: 89 44 24 04 mov %eax,0x4(%esp) 80483e8: c7 04 24 48 85 04 08 movl $0x8048548,(%esp) 80483ef: e8 e4 fe ff ff call 80482d8 <scanf@plt> 80483f4: 8b 45 f8 mov 0xfffffff8(%ebp),%eax 80483f7: 83 f8 7b cmp $0x7b,%eax 80483fa: 75 0e jne 804840a <main+0x46> 80483fc: c7 04 24 4b 85 04 08 movl $0x804854b,(%esp) 8048403: e8 c0 fe ff ff call 80482c8 <puts@plt> 8048408: eb 0c jmp 8048416 <main+0x52> 804840a: c7 04 24 54 85 04 08 movl $0x8048554,(%esp) 8048411: e8 b2 fe ff ff call 80482c8 <puts@plt> 8048416: b8 00 00 00 00 mov $0x0,%eax ... 8048423: c3 ret 080483c4 <main>: ... 80483d5: c7 04 24 38 85 04 08 movl $0x8048538,(%esp) 80483dc: e8 17 ff ff ff call 80482f8 <printf@plt> 80483e1: 8d 45 f8 lea 0xfffffff8(%ebp),%eax 80483e4: 89 44 24 04 mov %eax,0x4(%esp) 80483e8: c7 04 24 48 85 04 08 movl $0x8048548,(%esp) 80483ef: e8 e4 fe ff ff call 80482d8 <scanf@plt> 80483f4: 8b 45 f8 mov 0xfffffff8(%ebp),%eax 80483f7: 83 f8 7b cmp $0x7b,%eax 80483fa: 75 0e jne 804840a <main+0x46> 80483fc: c7 04 24 4b 85 04 08 movl $0x804854b,(%esp) 8048403: e8 c0 fe ff ff call 80482c8 <puts@plt> 8048408: eb 0c jmp 8048416 <main+0x52> 804840a: c7 04 24 54 85 04 08 movl $0x8048554,(%esp) 8048411: e8 b2 fe ff ff call 80482c8 <puts@plt> 8048416: b8 00 00 00 00 mov $0x0,%eax ......
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This note was uploaded on 10/19/2011 for the course CS 000 taught by Professor Jing during the Fall '10 term at Fudan University.

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lab2 - BE A Hacker Fudan University Parallel Processing...

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