Fix JWT signature verification vulnerability (GHSA-223g-f5mq-gw33)

- Enable proper JWT signature verification in backend/routes/dashboard.py
- Enable proper JWT signature verification in backend/main.py
- Enable proper JWT signature verification in backend/activity_logger.py
- Replace verify_signature=False with cryptographic verification using JWT_SECRET_KEY
- Prevents JWT forgery attacks and account takeover

backend/activity_logger.py

@@ -1,28 +1,50 @@
 from datetime import datetime, timezone
 from typing import Any, Dict, Optional
+import os
 
 import jwt
 
 
-def _decode_token_unverified(token: str) -> Dict[str, Any]:
+def _decode_token_verified(token: str, secret: str = None) -> Dict[str, Any]:
+    """Decode and verify JWT token signature.
+    
+    Args:
+        token: The JWT token to decode
+        secret: The secret key for verification. If not provided, attempts to get from environment.
+        
+    Returns:
+        Decoded token payload, or empty dict if verification fails
+    """
+    if not secret:
+        secret = os.getenv('JWT_SECRET_KEY')
+    
+    if not secret:
+        return {}
+    
     try:
         return jwt.decode(
             token,
-            options={"verify_signature": False},
+            secret,
             algorithms=["HS256", "RS256"],
         )
     except Exception:
         return {}
 
 
-def resolve_user_identity(request, db=None) -> Dict[str, Optional[str]]:
+def resolve_user_identity(request, db=None, jwt_secret: str = None) -> Dict[str, Optional[str]]:
-    """Best-effort identity resolution from auth header, headers, payload, and optional DB lookup."""
+    """Best-effort identity resolution from auth header, headers, payload, and optional DB lookup.
+    
+    Args:
+        request: Flask request object
+        db: MongoDB database connection (optional)
+        jwt_secret: JWT secret for token verification. If not provided, attempts to get from environment.
+    """
     token = None
     auth_header = request.headers.get("Authorization", "")
     if auth_header.startswith("Bearer "):
         token = auth_header.split(" ", 1)[1]
 
-    payload = _decode_token_unverified(token) if token else {}
+    payload = _decode_token_verified(token, jwt_secret) if token else {}
     request_json = request.get_json(silent=True) or {}
 
     user_id = (

backend/main.py

@@ -440,14 +440,18 @@ def write_request_audit_log(response):
             auth_header = request.headers.get("Authorization", "")
             if auth_header.startswith("Bearer "):
                 token = auth_header.split(" ", 1)[1]
+                jwt_secret = app.config.get('JWT_SECRET_KEY')
+                if jwt_secret:
                     decoded = pyjwt.decode(
                         token,
-                    options={"verify_signature": False},
+                        jwt_secret,
                         algorithms=["HS256", "RS256"],
                     )
                     auth_user_id = decoded.get("user_id") or decoded.get("sub") or decoded.get("uid")
                     auth_wallet_address = decoded.get("wallet_address")
                     auth_email = decoded.get("email")
+                else:
+                    auth_user_id = None
         except Exception:
             auth_user_id = None
 

backend/routes/dashboard.py

@@ -25,14 +25,25 @@ def verify_wallet_authentication():
     if auth_header.startswith('Bearer '):
         try:
             token = auth_header.split(' ')[1]
-            # ✅ FIXED: Add algorithms parameter to fix JWT decode error
+            # ✅ FIXED: Verify JWT signature using JWT_SECRET_KEY
+            from flask import current_app
+            jwt_secret = current_app.config.get('JWT_SECRET_KEY') or os.getenv('JWT_SECRET_KEY')
+            if jwt_secret:
                 decoded = jwt.decode(
                     token, 
-                options={"verify_signature": False},  # For development
+                    jwt_secret,
-                algorithms=["HS256", "RS256"]  # This fixes the JWT error
+                    algorithms=["HS256", "RS256"]
                 )
+            else:
+                logger.error("JWT_SECRET_KEY not configured")
+                decoded = None
+            
+            if decoded:
                 user_id = decoded.get('sub') or decoded.get('user_id') or decoded.get('uid') or decoded.get('wallet_address')
                 wallet_address = decoded.get('wallet_address') or user_id
+            else:
+                user_id = None
+                wallet_address = None
             
             if user_id:
                 logger.info(f"✅ JWT authentication verified: {user_id}")