Are COMET installations immune to “Slow TCP Reading” DoS on Windows? (Such as SignalR or WebSync)

Question

My understanding is that COMET implementations of WebSync and SignalR do not directly use IIS and are a few layers lower on the ISO model.

After reading Qualys's blog regarding slow TCP reading, I was wondering if this had any affect on COMET implementations since some are already using "long polling", websockets, or perhaps some other technique.

• Are COMET (or reverse AJAX) installations not vulnerable to this class of attack by design?

Answer 1

WebSync runs directly on top of the IIS/.NET stack, and so it relies on the Windows/IIS kernel to process TCP/HTTP for both long-polling and WebSocket transports. I believe SignalR does this as well.