HTB Challenge: A Nightmare On Math Street

nightmare.py

from pwn import *
import re


def adjust_operators(question: str) -> str:
    """Adjust the question to to make Addition and multiplication have the REVERSE order of operation"""
    question_adjusted = []
    during_plus_op = False
    for unit in question.split():
        if unit == "*":
            if during_plus_op:
                question_adjusted[-1] = f"{question_adjusted[-1]}) *"
                during_plus_op = False
            else:
                question_adjusted.append(unit)
            continue

        if unit == "+":
            # Check if next unit contains "("
            if question[question.index(unit)+1].startswith("("):
                question_adjusted.append(unit)
                continue
            if during_plus_op:
                question_adjusted[-1] = f"{question_adjusted[-1]} +"
            else:
                question_adjusted[-1] = f"({question_adjusted[-1]} +"
                during_plus_op = True
            continue

        question_adjusted.append(unit)

    if during_plus_op:
        question_adjusted[-1] += ")"

    question_adjusted_str = " ".join(question_adjusted)
    print(f"{question_adjusted_str=}")
    return question_adjusted_str

def solve_quesetion():
    """Solve the question and send the answer"""
    question_str = conn.recvuntil("?", timeout=1).decode()
    print(f"{question_str=}")
    question = re.findall(r"\[\d+\]:\s+(.*?)\s+\=", question_str)[0]
    print(f"{question=}")
    question_adjusted = adjust_operators(question)
    answer = str(eval(question_adjusted))
    print(f"{answer=}")

    conn.sendline(answer)
    print("\n---\n")
    if "[500]" in question_str:
        print(conn.recvline_contains("HTB", timeout=1).decode())
        exit(0)


global conn
conn = remote('165.227.237.190', 31344)

while 1:
    try:
        solve_quesetion()
    except EOFError:
        print("EOFError...")
        break