Improve banking website's security

1. Update your website regulary.
2. Change admin panel password regulary.
3. Put some security mechanism specially for avoiding SQL injection and Cross site scripting attack.
4. Put single website on single server so chances of hacking other website of same server not possible if one website is hacked.
5. If there is multiple user allowed to access admin panel then provide different rules for read or edit content.
6. Always keep backup copy of your website.
7. Install SSL layer security.
8. keep two way authentication for user.
9. Always encrypt secure data.
10. Use good antivirus at server.
11. Block all unnecessary internet access at server through strong firewall.