CTF-SHOW RE3

拿到题目分析

moke@moke:/mnt/d/ctf/ctf-show$ file r3
r3: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=db369095e7d1408227569c73862f91eb3fb4a2e8, not stripped

• DEV 调试 v16=0xE560

v16先加上v17[6]，然后判断是否大于0xffff，小于等于0xffff即退出循环
这里可以直接让v17[6]=0xffff-0xE560=0x1A9F，v16加上0x1A9F后即等于0xffff，然后退出循环

moke@moke:/mnt/d/ctf/ctf-show$ ./r3
plz input the key:
000001a9f0
OK

• flag{1a9f}