menu arrow_back 湛蓝安全空间 |狂野湛蓝,暴躁每天 chevron_right All_wiki chevron_right CTF-Writeup chevron_right GrabCON CTF 2021 chevron_right Reversing chevron_right Easy Rev
  • home 首页
  • brightness_4 暗黑模式
  • cloud
    xLIYhHS7e34ez7Ma
    cloud
    湛蓝安全
    code
    Github
    lightbulb_outline README

    Easy Rev

    Description

    Reverse Easy.....

    Solution

    First we execute the binary

    $ ./baby_re_2
    Looking for the flag?
    Enter the key: test
    Wrong! Try Again ...

    We try to analyze a binary to find the key using ghidra. We look up FUN_00101277 function and we see some interest. enter image description here First we look at line 19 we show a condition that will execute another function. And we see local_20 is an input variable and local_14 variable that equal = 0x140685(Hex). Since the integer variable is readed as decimal so we try to convert the value of local_14 to Decimal. 140685 (Hex) = 1312389 (Decimal)

    So we found the key and we try to execute again

    $ ./baby_re_2
    Looking for the flag?
    Enter the key: 1312389
    GrabCON{y0u_g0t_it_8bb31}

    We got flag!