Website login security

The front end – or the client-side – is considered the most vulnerable part of a website. As such, it is often targeted by cybercriminals looking to steal valuable customer data. Criminals will exploit third-party technologies to sneak in ‘the back door’ of a website. Leveraging live chat bots, social media buttons, CSS injection, keylogging, DDoS attack, trackers or advertisements to gain access to website visitors' personally identifiable information (PII). I need the support of a «security consultant» to verify (and correct/bugfix) specific login form placed into a website. I need to verify if current security controls that are in place are enough or new one is needed. I need a complete report about security bugs AND how to solve the issues. I need a technical and understandable document with actions (source code) to modify. Technologies: ASP pages and javascript. Windows server.