那真的牛批，啊，那真的牛批。

Problem: [JQCTF 2024 Final]s1gn@tur3

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思路

说中痛处就气急败坏，其实还是一条懒狗

EXP

from pwn import *
import itertools
import string
from hashlib import sha256


class Gao:
    def __init__(self):
        # self.conn = process(['python3', 'another.py'])
        self.conn = remote('node4.anna.nssctf.cn', '28822')
        self.username = b'Nu1L@root'
    
    def gao_sha256(self):
        s = self.conn.recvline().strip().decode()
        part2, ans = s[14:30], s[-64:]
        for i in itertools.product(string.ascii_letters + string.digits, repeat=4):
            part1 = ''.join(i)
            if sha256((part1+part2).encode()).hexdigest() == ans:
                print('SHA OK')
                self.conn.sendlineafter('XXXX:', part1)
                break
        else:
            raise Exception("SHA GG")
    
    def gao(self):
        self.gao_sha256()
        self.conn.sendlineafter(': ', self.username.hex())
        self.conn.recvuntil(': ')
        s = self.conn.recvline().strip()
        self.conn.sendlineafter(': ', self.username)
        self.conn.sendlineafter(': ', s)
        self.conn.interactive()

if __name__ == '__main__':
    g = Gao()
    g.gao()
​

总结

FUCK YOU