Re: Simple TCP service can hang a system

[jkonopka () ITOL COM (Joe Konopka)]

At 10:06 PM 6/21/97 -0400, you wrote:
> Willy TARREAU enscribed thusly:
>
> > Hi !
>
> > I've noticed that inetd doesn't check the source port for the request
> > to UDP simple services (echo, time, chargen, daytime).
>
> > This means it is possible to build a packet which will look like it comes
> > from one of these ports, to one of these ports. In this case, each UDP
> > response from the simple service will generate a new request to the source
> > port and the system or network can be quickly overloaded.

[parts deleted]

> > I tested Netware Client 32 for DOS/Windows, and it simply hangs. Not tested
> > yet on Win95/NT/Netware...

FYI, under WinNT 4.0, this causes 99% CPU usage in TCPSVCS.EXE, and can be
fixed by stopping and restarting "Simple TCP/IP services".