CTF Name : HackTheBox Challenges

Challenge category : Reversing

Challenge Name : Baby RE

Challenge points : 0 Points

Challenge desc : Show us your basic skills! (P.S. There are 4 ways to solve this, are you willing to try them all?)

Langsung saja kita kerjakan, yang pertama kita periksa terlebih dahulu type filenya dengan command ‘file’ seperti berikut.

$ file baby

baby: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=25adc53b89f781335a27bf1b81f5c4cb74581022, for GNU/Linux 3.2.0, not stripped

File tersebut adalah ELF64 Executable, selanjutnya kita coba lakukan command strings untuk melihat string pada program.

$ strings baby

/lib64/ld-linux-x86-64.so.2
mgUa
libc.so.6
puts
stdin
fgets
__cxa_finalize
strcmp
__libc_start_main
GLIBC_2.2.5
_ITM_deregisterTMCloneTable
__gmon_start__
_ITM_registerTMCloneTable
u/UH
HTB{B4BYH
_R3V_TH4H
TS_Ef
[]A\A]A^A_
Dont run `strings` on this challenge, that is not the way!!!!
Insert key:
abcde122313
Try again later.
;*3$"
GCC: (Debian 9.2.1-8) 9.2.1 20190909

Terlihat bahwa terdapat potongan flag, program meminta input dan dibawahnya terdapat string ‘abcde122313’, mari kita coba inputkan.

$ chmod +x baby
$ ./baby
Insert key:
abcde122313
HTB{B4BY_R3V_TH4TS_EZ}

Flag : HTB{B4BY_R3V_TH4TS_EZ}

Semoga bermanfaat:)