Description

The PHP source shows the encoding function: base64_encode(strrev(bin2hex($secret))). The encoded secret is visible. Reversing the operations recovers the original secret.

Overview

• The encoding is: hex-encode, reverse, base64-encode.
• The reverse is: base64-decode, reverse, hex-decode.
• bytes.fromhex() converts the hex string to the original bytes.

Solution

encoded = "3d3d516343746d4d6d6c315669563362"
step1 = base64.b64decode(encoded).decode()     # base64 decode
step2 = step1[::-1]                             # reverse
secret = bytes.fromhex(step2).decode()          # hex decode

response = requests.post(url, auth=("natas8", current_password), data={"secret": secret, "submit": ""})
result = re.search(r"The password for natas9 is (.*)", response.text).group(1).strip()

Password

Sda6t0vkOPkM8YeOZkAGVhFoaplvlJFd