dontpanico / jwtxploiter

A tool to test security of json web token

jwtXploiter

A tool to test security of JSON Web Tokens. Test a JWT against all known CVEs;

• Tamper with the token payload: changes claims and subclaims values.
• Exploit known vulnerable header claims (kid, jku, x5u)
• Verify a token
• Retrieve the public key of your target's ssl connection and try to use it in a key confusion attack with one option only
• All JWAs supported
• Generates a JWK and insert it in the token header
• And much, much more!

Wiki

• Read the wiki! wiki

Installation

N.B. Cloning the repository should be avoided except for development purposes! N.B. Deb package has to be considered beta

• With rpm:

  wget http://andreatedeschi.uno/jwtxploiter/jwtxploiter-1.2.1-1.noarch.rpm
  sudo rpm --install jwtxploiter-1.2.1-1.noarch.rpm

  or, if previous version is installed on your machine

  sudo rpm --upgrade jwtxploiter-1.2.1-1.noarch.rpm

• With pip:

  sudo pip install jwtxploiter

• With deb:

  wget http://andreatedeschi.uno/jwtxploiter/jwtxploiter_1.2.1-1_all.deb
  sudo dpkg -i jwtxploiter_1.2.1-1_all.deb

• Cloing the repo:

  git clone https://github.com/DontPanicO/jwtXploiter.git
  ./install.sh

N.B. python3-pip package is required to install dependencies, be sure to have it installed.

Who this tool is written for?

• Web Application Penetration Tester / Bug Bounty Hunters

  • This tool has been written with the aim of become a key part of pentesters toolkit.

• Devs who need to test the secuirty of JWTs used in their applications

• CTF Players

• Not For Students

  • Since this tool automates lot of stuff, without force the user to know what's happening under the hood, it won't help you to understand the vulnerabilities it exploits.

To Know

• For attacks that generates a jwks file, you could find it in the current working directory. Remeber to deletes such files in order to avoid conflicts.

• For jku/x5u injection that needs to merge two urls (the server vulnerable url and your one), the HERE keyword is required.

• For redirect attacks the keyword should replace the redirect url, e.g.

  • http://app.com/foo?redirect=bar&some=thing --> http://app.com/foo?redirect=HERE&some=thing

• For jku/x5u injections via HTTP header injection attacks, the HERE keyword sould be appended to the vulnerable parameter, without replacing its value, e.g.

  • http://app.com/foo?param=value --> http://app.com/foo?param=valueHERE

• Also, in such cases, be sure to pass the server url and your one as comma separated values.

• '/.well-known/jwks.json' is automatically appended to your url in jku/x5u attacks. So make sure to place the jwks file under this path on your server.

• If you don't want that happen, use the --manual option, but this option is compatible only with --jku-basic and --x5u-basic so, you will need to manually craft the url and pass it to those options, even for attacks that exploit Open Redirect or HTTP header injection.

• Look at the wiki for a detailed documentation.

jwtxploiter's Issues

Installation script may miss to install requirements

I noticed that sometimes install.sh miss to call pip3 install -r requirements.txt. So if when you run the main script you get a depndency-related error, do that manually.

FileNotFoundError when passing non existing key file to -k/--key

Describe the bug
Exception FileNotFoundError not properly handled, when passing a non existing key file to -k/--key.
This happen only with asymmetric algorithms, since it's been handled with HS*

To Reproduce

1. Get a valid JWT (you can grab it from jwt.io)
2. Run an attack using an asymmetric algorithm and passing a non existing key file to -k

   jwtxpl <token> -a rs256 -p <key>:<value> -k /path/to/non/existing

Expected behavior
The script should properly handle this exception and return a custom error

CLOSED!!! UnboundLocalError with none algortihm

• Before time of writing, selecting alg none will raise an exceptions. This is due since during validation the script converts algorithms
  to uppercase, but the method which select the signature only look for 'none' or 'None'.

• SOLVED, converting algorithm to uppercase only if its lowercase differ from 'none'.

• I WILL LEAVE THE ISSUE OPENED 3 DAYS IN ORDER TO MAKE IT MORE VISIBLE TO PEOPLE RAN INTO THAT ERROR.

FileNotFoundError when passing unexisting keys to -k/--key with algorithm different from HS*

N.B. THIS ISSUE HAS BEEN CLOSED! THE EXCEPTION HAS BEEN HANDLED!

• Before time of writing, FileNotFoundError generated from non existing files passed to -k/--key, was handled only with HS*
  algorithms.

• Now, after last commit, the exception has been handled, no matter which alg has been passed.

AttributeError if jwks file does not contain the verifier key

Describe the bug
Running --find-key-from-jwks raise AttributeError if jwks file does not contain a key that can verify the token

To Reproduce

1. Get a token
2. Get a JWKS file that does not contain the key that can verify the token signature
3. run jwtxpl <token> --find-key-from-jwks <jwks_file>

Expected behavior
No AttributeError should be raised

Additional context
This is due to a typo an attribute has been typed incorrectly), and not for an unhandled exception

JWKS file not properly generated

Describe the bug
Jku and x5u attacks that return jwks files miss to generates it.

To Reproduce
Run a jku/x5u attack against a valid target (not --jku-inbody and --x5u-inbody, since they does not returns jwks files)

Expected behavior
The tool should return the crafted jwks file