Web Forms is an older ASP.NET application model built around server controls, page lifecycle events, and hidden state such as ViewState. Instead of treating each request as a mostly independent page load, Web Forms maintains a more stateful programming model that lets controls remember values and behavior between requests.
This matters in security because stateful features create extra trust boundaries. If ViewState, control data, file upload logic, or related cryptographic handling is misconfigured or flawed, attackers may be able to tamper with application state, recover sensitive information, or chain a small weakness into server-side impact. In real attacks, Web Forms applications often expose legacy third-party controls, custom event handlers, and encrypted state formats that were designed for convenience rather than minimal attack surface. Defenders should inventory these apps, keep the underlying framework and controls patched, disable unnecessary features, protect state with strong keys and validation, and review error handling because visible differences in failure responses can become attack signals.