Exploitation Tools

Padding-Oracle-Attacker – Execute Padding Oracle Attacks Easily

Padding-Oracle-Attacker - CLI Tool And Library To Execute Padding Oracle Attacks Easily

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CLI tool and library to execute padding oracle attacks easily, with support for concurrent network requests and an elegant UI.

Make sure Node.js is installed, then run

$ npm install --global padding-oracle-attacker


$ yarn global add padding-oracle-attacker

CLI Usage

  $ padding-oracle-attacker decrypt <url> hex:<ciphertext_hex> <block_size> <error> [options]
  $ padding-oracle-attacker decrypt <url> b64:<ciphertext_b64> <block_size> <error> [options]
$ padding-oracle-attacker encrypt <url> <plaintext> <block_size> <error> [options]
$ padding-oracle-attacker encrypt <url> hex:<plaintext_hex> <block_size> <error> [options]
$ padding-oracle-attacker analyze <url> [<block_size>] [options]
decrypt Finds the plaintext (foobar) for given ciphertext (hex:0123abcd)
encrypt Finds the ciphertext (hex:abcd1234) for given plaintext (foo=bar)
analyze Helps find out if the URL is vulnerable or not, and
how the response differs when a decryption error occurs
(for the <error> argument)
<url> URL to attack. Payload will be inserted at the end by default. To specify
a custom injection point, include {POPAYLOAD} in a header (-H),
request body (-d) or the URL
<block_size> Block size used by the encryption algorithm on the server
<error> The string present in response when decryption fails on the server.
Specify a string present in the HTTP response body (like PaddingException)
or status code of the HTTP response (like 400)
-c, --concurrency Requests to be sent concurrently [default: 128]
--disable-cache Disable network cache. Saved to [default: false]
poattack-cache.json.gz.txt by default
-X, --method HTTP method to use while making request [default: GET]
-H, --header Headers to be sent with request.
-H 'Cookie: cookie1' -H 'User-Agent: Googlebot/2.1'
-d, --data Request body
JSON string: {"id": 101, "foo": "bar"}
URL encoded: id=101&foo=bar
Make sure to specify the Content-Type header.
-e, --payload-encoding Ciphertext payload encoding for {POPAYLOAD} [defa ult: hex]
base64 FooBar+/=
base64-urlsafe FooBar-_
hex deadbeef
hex-uppercase DEADBEEF
base64(xyz) Custom base64 ('xyz' represent characters for '+/=')
--dont-urlencode-payload Don't URL encode {POPAYLOAD} [default: false]
--start-from-1st-block Start processing from the first block instead [default: false]
of the last (only works with decrypt mode)
$ poattack decrypt http://localhost:2020/decrypt?ciphertext=
16 400
$ poattack encrypt http://localhost:2020/decrypt?ciphertext= "foo bar 🦄" 16 400
$ poattack encrypt http://localhost :2020/decrypt?ciphertext= hex:666f6f2062617220f09fa684 16 400
$ poattack analyze http://localhost:2020/decrypt?ciphertext=

Library API

const { decrypt, encrypt } = require('padding-oracle-attacker')
// or
import { decrypt, encrypt } from 'padding-oracle-attacker'
const { blockCount, totalSize, foundBytes, interBytes } = await decrypt(options)
const { blockCount, totalSize, foundBytes, interBytes, finalRequest } = await encrypt(options)

decrypt(options: Object): Promise

encrypt(options: Object): Promise

Required options

url: string
URL to attack. Payload will be appended at the end by default. To specify a custom injection point, include {POPAYLOAD} in the URL, a header (requestOptions.headers) or the request body (requestOptions.data)

blockSize: number
Block size used by the encryption algorithm on the server.

isDecryptionSuccess: ({ statusCode, headers, body }) => boolean
Function that returns true if the server response indicates decryption was successful.

ciphertext: Buffer (decrypt only)
Ciphertext to decrypt.

plaintext: Buffer (encrypt only)
Plaintext to encrypt. Padding will be added automatically. Example: Buffer.from('foo bar', 'utf8')

Optional options

concurrency: number = 128
Network requests to be sent concurrently.

isCacheEnabled: boolean = true
Responses are cached by default and saved to poattack-cache.json.gz.txt. Set to false to disable caching.

requestOptions: { method, headers, data }

requestOptions.method: string
HTTP method to use while making the request. GET by default. POST, PUT, DELETE are some valid options.

requestOptions.headers: { string: string }
Headers to be sent with request. Example: { 'Content-Type': 'application/x-www-form-urlencoded' }

requestOptions.body: string
Request body. Can be a JSON string, URL encoded params etc. Content-Type header has to be set manually.

logMode: 'full'|'minimal'|'none' = 'full'
full: Log everything to console (default)
minimal: Log only after start and completion to console
none: Log nothing to console

transformPayload: (ciphertext: Buffer) => string
Function to convert the ciphertext into a string when making a request. By default, ciphertext is encoded in hex and inserted at the injection point (URL end unless {POPAYLOAD} is present).

Optional options (decrypt only)

alreadyFound: Buffer
Plaintext bytes already known/found that can be skipped (from the end). If you provide a Buffer of ten bytes, the last ten bytes will be skipped.

initFirstPayloadBlockWithOrigBytes: boolean = false
Initialize first payload block with original ciphertext bytes instead of zeroes.
Example: abcdef12345678ff 1111111111111111 instead of 00000000000000ff 1111111111111111

startFromFirstBlock: boolean = false
Start processing from the first block instead of the last.

makeInitialRequest: boolean = true
Make an initial request with the original ciphertext provided and log server response to console to allow the user to make sure network requests are being sent correctly.

Optional options (encrypt only)

makeFinalRequest: boolean = true
After finding the ciphertext bytes for the new plaintext, make a final request with the found bytes and log the server response to console.

lastCiphertextBlock: Buffer
Custom ciphertext for the last block. Last block is just zeroes by default (000000000000000).

padding-oracle-attacker is written in TypeScript. If you’d like to modify the source files and run them, you can either compile the files into JS first and run them using node, or use ts-node.
Example: yarn build then node dist/cli ... or simply ts-node src/cli ...

yarn build or npm run build
Builds the TypeScript files inside the src directory to JS files and outputs them to the dist directory.

yarn clean or npm run clean
Deletes the dist directory.

yarn lint or npm run lint
Lints the files using eslint.

yarn test or npm run test
Lints and runs the tests using ava.

node test/helpers/vulnerable-server.js
Runs the test server which is vulnerable to padding oracle attacks at http://localhost:2020


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