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3204, 13/161 |
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movestar | |||||||
¼¿ÄÚµå ¸¸µé±â¿¡¼... | |||||||
http://www.hackerschool.org/HS_Boards/zboard.php?id=QNA_programming&no=2035 [º¹»ç]
Hit : 2705 Date : 2009/05/21 04:52
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movestar | .globl main main: jmp come_here func: movl $0x0b, %eax popl %ebx add $0x4, %ebx push %ebx movl %esp, %ecx movl $0x00, %edx int $0x80 movl $0x01, %eax movl $0x00, %ebx int $0x80 come_here: call func .string " /bin/sh\00" ÀÌ·¸°Ô Çؼ ecx ¿¡ /bin/sh ¸¦ °¡¸®Å°´Â Æ÷ÀÎÅ͸¦ ³Ö¾î¼ eax, ebx, ecx, edx¿¡ ´Ù Á¦´ë·Î °ªÀ» ³ÖÀº°Í °°Àºµ¥ ½ÇÇàÇصµ ½©ÀÌ ¾È¶ß³×¿ä. |
2009/05/21 | |
ArtHacker7 | eax = 0xb edx = 0x0 (¼¼¹ø°ÀÎÀÚ) ebx = ù¹ø°ÀÎÀÚ "/bin/sh" ecx = µÎ¹ø°ÀÎÀÚ "/bin/sh"+0 ±ÛÀ» ÀÚ¼¼È÷ ¾ÈÀоîºÁ¼± ¸ð¸£°ÚÁö¸¸ ½©ÄÚµå ½ÇÇàÇϴµ¥ int $0x80ÀÌ 2¹øÀ̳ª µé¾î°¥ ÇÊ¿æ ¾ø¾î¿ä. ÀÎÀÚ 4°³¸¦ ³Ö¾îÁÖ´Â ÄÚµå¿Í ÀÎÅÍ·´Æ® È£ÃâÇÏ´Â ÄÚµå Çϳª¸¸ ÀÖÀ¸¸é ½©ÄÚµå´Â ½ÇÇàµË´Ï´Ù. |
2009/05/21 | |
ArtHacker7 | ebx ecx¿¡ µé¾î°¡´Â°Ç ´ç¿¬È÷ ½ÃÀÛÁÖ¼Ò¿¡¿ä... | 2009/05/21 | |
sjh21a | ½ºÅÿ¡ ½ÇÇà ±ÇÇÑÀÌ ¾ø´Â°Å °°³×¿ä cat /proc/self/maps Çؼ stack ¿¡ x ÀÖ³ª üũ ÇÏ½Ã°í ¾øÀ¸½Ã¸é ½©ÄÚµå Å×½ºÆ® ÇÏ½Ç ¶§gcc ¿É¼ÇÀ¸·Î gcc -o a a.c -z execstack ÁÖ½É µÇ¿ä |
2009/05/22 | |
movestar | ½ºÅà ±ÇÇÑÀÌ ¾ø´Â°ÍÀº ¸Â´Âµ¥, À߸𸣰ÚÁö¸¸ »ó°üÀÌ ¾ø´Â°Å °°¾Æ¿ä ¼Ò½º¸¦ .globl main main: jmp come_here func: movl $0x0b, %eax popl %ebx addl $0x04, %ebx pushl %ebx movl %esp, %ecx movl $0x00, 0x4(%esp) movl $0x00, %edx int $0x80 movl $0x01, %eax movl $0x00, %ebx int $0x80 come_here: call func .string " /bin/sh\00" ÀÌ·¸°Ô ¹Ù²Ù°í -z execstack ¿É¼Ç ÁذŶû ¾ÈÁذŶû ¸ðµÎ Á¤»óÀûÀ¸·Î /bin/sh °¡ ½ÇÇàµÇ³×¿ä man execve ¿¡¼ argv´Â »õ·Î¿î ÇÁ·Î±×·¥Àº Åë°úÇÏ´Â Àμö ¹®ÀÚ¿ÀÇ ¹è¿ÀÌ´Ù. envp´Â Áø ºÎ ÇÏ °Ôµµ key=valueÇüÅÂÀÇ ¹®ÀÚ¿ ¹è¿ÀÌ´Ù. ±×°ÍÀº »õ·Î¿î ÇÁ·Î±×·¥À¸·Î ȯ °æó·³ Àü´ÞµÈ´Ù. "argv¿Í envp´Â ¸ðµÎ nullÆ÷ÀÎÅÍ¿¡ ÀÇÇØ Á¾·áµÇ¾î¾ß¸¸ ÇÑ ´Ù." ¿©±â¼ null Æ÷ÀÎÅÍ·Î Á¾·áµÇ¾î¾ß ÇÑ´Ù... ±×·¡¼ c·ÎµÈ ÇÁ·Î±×·¥¿¡¼ execve ½ÇÇàµÉ¶§ ecx¿¡ ÀúÀåµÈ ´ÙÀ½ 4byte ¸¦ º¸´Ï±î 0x00.. ¾î¼À¼Ò½º¿¡µµ ecx ´ÙÀ½À» 0x00À¸·Î ÇÏ´Ï±î ½ÇÇàÀÌ µÇ³×¿ä Àß ¾ÈµÇ¼ ±×¸¸µÑ·Á°í Çߴµ¥ ÀºÐµéÀÌ °ü½É°¡Á®Áּż ³¡±îÁö ÇÒ ¼ö ÀÖ¾ú½À´Ï´Ù. °¨»çÇÕ´Ï´Ù~ °Áº¸°í ÇѰǵ¥ ³ª¸§ Èå¹µÇÏ³×¿ä ¤¾¤¾ |
2009/05/22 | |
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