Rustpad : Multi-Threaded Padding Oracle Attacks Against Any Service

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Rustpad is a multi-threaded successor to the classic padbuster, written in Rust. It abuses a Padding Oracle vulnerability to decrypt any cypher text or encrypt arbitrary plain text without knowing the encryption key!

 Features

  • Decryption of cypher texts
  • Encryption of arbitrary plain text
  • Multi-threading on both block and byte level
  • Modern, real-time and interactive TUI!
  • No-TTY support, so you can just pipe output to a file
  • Supports Web server oracles…
  • … and Script-based oracles. For when you need just that extra bit of control.
  • Automated calibration of web oracle’s (in)correct padding response
  • Progress bar and automated retries
  • Tab auto-completion
  • Block-level caching
  • Smart detection of cypher text encoding, supporting: hexbase64base64url
  • No IV support
  • Written in purely safe Rust, making sure you don’t encounter nasty crashes

 Usage

Using rustpad to attack a padding oracle is easy. It requires only 4 pieces of information to start:

  • type of oracle (web/script, see below)
  • target oracle (--oracle)
  • cypher text to decrypt (--decrypt)
  • block size (--block-size)

Web mode

Web mode specifies that the oracle is located on the web. In other words, the oracle is a web server with a URL.

For a padding oracle attack to succeed, an oracle must say so if a cypher text with incorrect padding was provided. rustpad will analyse the oracle’s responses and automatically calibrate itself to the oracle’s behaviour.

rustpad web –help
rustpad-web 1.8.0
Question a web-based oracle
USAGE:
rustpad {web, –web, -W} [OPTIONS] –oracle –block-size –decrypt
OPTIONS:
-A, –user-agent
User-agent to identify with
[default: rustpad/1.8.0]
-B, –block-size
Block size used by the cypher
[options: 8, 16]
-c, –consider-body
Consider the response body and content length when determining the web oracle’s response to (in)correct padding
-d, –data
Data to send in a POST request
-D, –decrypt
Original cypher text, received from the target service, which is to be decrypted
–delay
Delay between requests within a thread, in milliseconds
[default: 0]
-e, –encoding
Specify encoding used by the oracle to encode the cypher text
[options: auto, hex, base64, base64url]
[default: auto]
-E, –encrypt
Plain text to encrypt. Note: encryption mode requires a cypher text to gather necessary data
-h, –help
Print help information
-H, –header
HTTP header to send
[format: :]
-k, –insecure
Disable TLS certificate validation
-K, –keyword
Keyword indicating the location of the cypher text in the HTTP request. It is replaced by the cypher text’s value at runtime
[default: CTEXT]
-n, –no-iv
Cypher text does not include an Initialisation Vector
–no-cache
Disable reading and writing to the cache file
–no-url-encode
Disable URL encoding and decoding of cypher text
-o, –output
File path to which log output will be written
-O, –oracle
The oracle to question with forged cypher texts. This can be a URL or a shell script.
See the subcommands web --help and script --help respectively for further help.
–proxy-credentials
Credentials to authenticate against the proxy server with
[format: :]
-r, –redirect
Follow HTTP Redirects
-t, –threads
Amount of threads in the thread pool
[default: 64]
-T, –timeout
Web request timeout in seconds
[default: 10]
-v, –verbose
Increase verbosity of logging
-V, –version
Print version information
-x, –proxy
Proxy server to send web requests over. Supports HTTP(S) and SOCKS5
Indicate the cypher text’s location! See --keyword for clarification.

Script mode

Script mode was made for power users or CTF players 🏴‍☠️ who were given a script to run. The target oracle is a local shell script.

Scripts allow you to run attacks against local oracles or more exotic services. Or you can use script mode to customize and extend rustpads features. However, if you’re missing a feature, feel free to open an issue on GitHub!

rustpad script –help
rustpad-script 1.8.0
Question a script-based oracle
USAGE:
rustpad {script, –script, -S} [OPTIONS] –oracle –block-size –decrypt
OPTIONS:
-B, –block-size
Block size used by the cypher
[options: 8, 16]
-D, –decrypt
Original cypher text, received from the target service, which is to be decrypted
–delay
Delay between requests within a thread, in milliseconds
[default: 0]
-e, –encoding
Specify encoding used by the oracle to encode the cypher text
[options: auto, hex, base64, base64url]
[default: auto]
-E, –encrypt
Plain text to encrypt. Note: encryption mode requires a cypher text to gather necessary data
-h, –help
Print help information
-n, –no-iv
Cypher text does not include an Initialisation Vector
–no-cache
Disable reading and writing to the cache file
–no-url-encode
Disable URL encoding and decoding of cypher text
-o, –output
File path to which log output will be written
-O, –oracle
The oracle to question with forged cypher texts. This can be a URL or a shell script.
See the subcommands web --help and script --help respectively for further help.
-t, –threads
Amount of threads in the thread pool
[default: 64]
-v, –verbose
Increase verbosity of logging
-V, –version
Print version information
Script must respond with exit code 0 for correct padding, and any other code otherwise. Cypher text is
passed a
s the 1st argument.

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