search

roaris / ctf-log

0 stars 0 forks source link

picoCTF: GDB baby step 3 (Reverse Engineering) #19

Open roaris opened 6 months ago

roaris commented 6 months ago

https://play.picoctf.org/practice/challenge/397

roaris commented 6 months ago 
[-------------------------------------code-------------------------------------]
   0x401106 <main>:     endbr64
   0x40110a <main+4>:   push   rbp
   0x40110b <main+5>:   mov    rbp,rsp
=> 0x40110e <main+8>:   mov    DWORD PTR [rbp-0x14],edi
   0x401111 <main+11>:  mov    QWORD PTR [rbp-0x20],rsi
   0x401115 <main+15>:  mov    DWORD PTR [rbp-0x4],0x2262c96b
   0x40111c <main+22>:  mov    eax,DWORD PTR [rbp-0x4]
   0x40111f <main+25>:  pop    rbp

となっているので、mov DWORD PTR [rbp-0x4],0x2262c96bの実行後まで進める

リトルエンディアンで格納されている

gdb-peda$ x/4bx $rbp-4
0x7fffffffdf4c: 0x6b    0xc9    0x62    0x22

picoCTF{0x6bc96222}がフラグ