Fix access control vulnerability in get_note endpoint by restricting note access to the authenticated user only.

[zeropath-ai-dev]

Summary

• The Vulnerability Description:
  The get_note endpoint allowed authenticated users to access notes that did not belong to them by only checking the note ID and not verifying note ownership, enabling attackers to enumerate or guess IDs and retrieve other users’ notes.

• This Fix:
  The endpoint now restricts note access to only the authenticated user’s notes, ensuring users can only view notes associated with their own account.

• The Cause of the Issue:
  The original implementation iterated over all users’ notes without filtering by the currently authenticated user, leading to unsafe exposure of data across user accounts.

• The Patch Implementation:
  The patched code retrieves notes only for the logged-in user using their user ID from the session, and searches for the note ID within this user-specific list, preventing unauthorized cross-user access.

Vulnerability Details

• Vulnerability Class: Insecure Direct Object Reference (IDOR)
• Severity: 7.0
• Affected File: main.py
• Vulnerable Lines: 87-96

Code Snippets

diff --git a/main.py b/main.py
index 2454076..9f45c0b 100644
--- a/main.py
+++ b/main.py
@@ -86,13 +86,14 @@ def get_user():
 
 @app.route('/note/<int:note_id>', methods=['GET'])
 def get_note(note_id):
-    if 'user_id' not in session:
+    user_id = session.get('user_id')
+    if user_id is None:
         return jsonify({"error": "Please log in"}), 401
 
-    for user_notes in notes.values():
-        for note in user_notes:
-            if note['id'] == note_id:
-                return jsonify(note), 200
+    user_notes = notes.get(user_id, [])
+    for note in user_notes:
+        if note['id'] == note_id:
+            return jsonify(note), 200
 
     return jsonify({"error": "Note not found"}), 404
 

How to Modify the Patch

You can modify this patch by using one of the two methods outlined below. We recommend using the @zeropath-ai-dev bot for updating the code. If you encounter any bugs or issues with the patch, please report them here.

Ask @zeropath-ai-dev!

To request modifications, please post a comment beginning with @zeropath-ai-dev and specify the changes required.

@zeropath-ai-dev will then implement the requested adjustments and commit them to the specified branch in this pull request. Our bot is capable of managing changes across multiple files and various development-related requests.

Manually Modify the Files

# Checkout created branch:
git checkout zvuln_fix_insecure_direct_object_reference_idor_1750792680463179

# if vscode is installed run (or use your favorite editor / IDE):
code main.py

# Add, commit, and push changes:
git add -A
git commit -m "Update generated patch with x, y, and z changes."
git push zvuln_fix_insecure_direct_object_reference_idor_1750792680463179