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PHP Crypto Challenge
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| """<?php | |
| function source() { // require("key.php"); | |
| echo "<pre>"; | |
| highlight_string(file_get_contents(__FILE__)); | |
| echo "</pre>"; | |
| } | |
| function quit() { | |
| // source(); | |
| die(); | |
| } | |
| function encrypt($input) { // OPENSSL_RAW_DATA=1 | |
| $res = openssl_encrypt($input, "AES-128-ECB", "biglongsecretkey", 1); | |
| return $res; // bin2hex(openssl_random_pseudo_bytes(8)) | |
| } | |
| function decrypt($input) { | |
| $res = openssl_decrypt($input, "AES-128-ECB", "biglongsecretkey", 1); | |
| return $res; | |
| } | |
| if (!isset($_COOKIE["key"])) { | |
| $username = (isset($_GET["username"])) ? $_GET["username"] : "guest"; | |
| $password = (isset($_GET["password"])) ? $_GET["password"] : "guest"; | |
| if (preg_match("/admin=1/i", $username) || preg_match("/admin=1/i", $password)) { quit(); } | |
| $cookieenc = encrypt("name=$username;admin=0;password=$password;userid=1337"); | |
| setcookie("key", base64_encode($cookieenc)); $_COOKIE["key"] = base64_encode($cookieenc); | |
| } | |
| if (strpos(decrypt(base64_decode($_COOKIE["key"])), "admin=1") !== false) { | |
| echo "Bravo, you can validate with the following flag: " . "M01_J41M3_L35_GR0535_L4MPE5"; | |
| die(); // echo "<img src='https://media.giphy.com/media/H6CDICYUiPAwE/giphy.gif'/><br>"; | |
| } else { | |
| echo "Plaintext cookie : " . decrypt(base64_decode($_COOKIE["key"])) . "<br>"; quit(); | |
| } | |
| // source(); ?>""" | |
| def flag(): # php -S localhost:1234 | |
| c = __import__("requests").utils.unquote(__import__("requests").get("http://localhost:1234/chall.py.php?username=aaaaaadmin=&password").cookies.get_dict()["key"]) | |
| d = [c[i:i+22-1] for i in range(0, len(c), 22-1)] | |
| for i in range(1, 65+1): | |
| for k in __import__("itertools").permutations(__import__("string").printable[:65], i): | |
| key = d[0] + "".join(k) + d[1][len(k):] + d[2] + d[3] + "======" | |
| x = __import__("requests").post("http://localhost:1234/chall.py.php", cookies={"key":key}) | |
| y, z = __import__("re").search(r"Plaintext cookie.*1337", x.text), __import__("re").search(r"Bravo.*", x.text) | |
| if x is not None and y is None and z is not None: _ = exit((key, z.group())) if len(x.text) <= 100 else 0 | |
| if "".join(k)[-1::] == "Z": print(key) | |
| flag() |
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