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   vngkv123
   gdb¿¡¼­ callÀÌÈÄ ºê·¹ÀÌÅ©¸¦ °É¾úÀ»¶§..

http://www.hackerschool.org/HS_Boards/zboard.php?AllArticle=true&no=1841 [º¹»ç]


0x0804855c <main+103>:        call   0x80483c8 <<< fgets
0x08048561 <main+108>:        add    esp,0x10   <<< b* main+108°É°í rÇÑ »óÅÂ

ÀÌ·² ¶§, ÀÌ ´ÙÀ½ ÁÖ¼Ò¿¡¼­ ºê·¹ÀÌÅ©¸¦ °É¾úÀ» ¶§, esp-4°¡ retÀ̶ó´Âµ¥

call¿¡ ÀÇÇØ fgets¸í·ÉÀÌ ÀüºÎ ½ÇÇàµÇ°í ÇÔ¼öÀÇret¿¡¼­ pop eipÀÌÈÄ jmp eip¸¸ ½ÇÇàÀÌ ¾ÈµÈ »óÅÂÀΰ¡¿ä?? ºê·¹ÀÌÅ©¸¦ °É¾î¼­???

  Hit : 2737     Date : 2017/03/31 12:47



    
pwnnnt step in / step over µÑ Áß ¾î¶²°É ÇϼÌÁÒ ? 2017/03/31  
pwnnnt ¾Æ main ÇÔ¼ö¿¡¼­ call <fgets()>¸¦ ÇÑ ´ÙÀ½ ÁÖ¼Ò¸¦ ¸»ÇϽô °Ç°¡¿ä ? 2017/03/31  
vngkv123 ³× gdb»ó ±×³É call<fegts>´ÙÀ½¿¡ b *·Î °É¾ú¾î¿ä 2017/03/31  
vngkv123 0x0804855c <main+103>: call 0x80483c8
0x08048561 <main+108>: add esp,0x10 <<<< ¿©±â¿¡

b *main+108À¸·Î °ÉÀº»óÅÂÀ̰í Àú°Å ÄÝÇÏ´Â°Ç fgetsÇÔ¼öÀÔ´Ï´Ù.
2017/03/31  
pwnnnt ±×·¸´Ù¸é jmp eip µÈ »óÅÂÀÔ´Ï´Ù. 2017/03/31  
pwnnnt 0x08048561 <main+108>: add esp,0x10

À̰Ŵ ÇÔ¼öÈ£Ãâ±Ô¾Ç º¸½Ã¸é ¾Ë°ÚÁö¸¸, ÇÔ¼ö ³¡³­ µÚ ½ºÅÿ¡¼­ ÀÎÀÚ¸¦ Á¤¸®ÇÏ´Â °ÍÀÔ´Ï´Ù.
2017/03/31  
vngkv123 Ãß°¡ Áú¹® Çϳª¸¸ ÇØº¼°Ô¿© ¤Ð

low addr high addr
~~ | sfp | ret | argv1 | argv2 | argv3....ÀÌ·±½ÄÀ¸·Î ½×ÀÏÅÙµ¥

¸®ÅϱîÁö ÁøÇàµÇ¸é µÚÀÇ argvµéÀº ¾Ë¾Æ¼­ Á¤¸®µÇ´Â°Ç°¡¿ä?? ¾Æ´Ï¸é ½ºÅÿ¡ ³²¾ÆÀÖ³ª¿ä??
À§ÀÇ fgets°¡ ÁøÇàµÇ¾úÀ»¶§¿ä
2017/03/31  
vngkv123 ¾Æ¾Æ¾Æ¾Æ ±×·¸³×¿ä ¤»¤»¤» ¾Ë°Ú½À´Ï´ç ! 2017/03/31  
pwnnnt ÇÔ¼ö È£Ãâ ±Ô¾àÀε¥ ±Ô¾ÇÀ̶ó°í Àû¾î³ù³×¿ä ;¤±;

low addr¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡ high addr
fgets stack | sfp, main()_ebp | ret, <main+108> | argv1 | argv2 | argv3...

ÀÔ´Ï´Ù.
2017/03/31  
pwnnnt ÀÎÀÚÁ¤¸®´Â ÀÌÇØ°¡½Å°Í °°¾Æ¼­.. µû·Î ¾ÈÀû¾ú½À´Ï´Ù ! 2017/03/31