✅ Understand whether “index” refers to character position or version number. ✅ Check logs to see if index increments correctly after each password change. ✅ Implement index validation to prevent reuse of old passwords. ✅ Do not reveal index to ordinary users. ✅ Test edge cases: first password set, reset after expiry, history cleared.
Example code (Python) to track index:
Move any folder containing passwords out of the public webroot (e.g., to /home/user/secure/ ). If it must stay, add .htaccess with: index of password new
| Error Message | Likely Cause | Solution | |---------------|--------------|----------| | Invalid index of password new | Negative or zero index passed | Ensure index starts at 1. | | Index of password new out of range | Array bound error in code | Check loop limits (e.g., index < len(new_password) ). | | Duplicate index detected | Two password changes got same sequence number | Add atomic counter in DB. | ✅ Do not reveal index to ordinary users