Overview
We are given an encoded base64 payload representing a URL.
Reconnaissance
Decoding the base64 string yields a Google Drive sharing link for a video file.
Exploitation Strategy
Downloading the video, we notice a ciphertext embedded in the filename: RUFzj5oo5^ui1s`oeit^q55st^mdxxx. Performing a XOR decryption on the string using a key of 1 yields the flag.
Solution Code
def xor_decrypt(cipher, key):
return ''.join(chr(ord(c) ^ key) for c in cipher)
cipher = "RUFzj5oo5^ui1s`oeit^q55st^mdxxx"
print(xor_decrypt(cipher, 1)) # -> STG{k4nn4_th0randhu_p44ru_leyyy}Flag
STG{k4nn4_th0randhu_p44ru_leyyy}