RDP Denial of Service in XP Pro

[Guest]

My XP Pro (and firewall) at home is configured to allow Remote Desktops and
my wife and I alternate connecting to it over the internet. Since recently
I've started experiencing denial of service that manifests by a black creen
when the RDP client connects. Logging on on the console usually resets the
issue. The eventviewer has error messages from TERMDD and termserv that
invalid packet was received and the client was disconnected.

Note that the client is not disconnected: it just shows a black screen for
ever and never disconnects until I disconnect it.

I searched msft for black screen and RDP and saw that this symptom could
happen if an intermediate router drops large packets and the suggestion was
to reduce the MTU size.

Now I've noticed that I usually experience the denial of service after my
wife tries to connect. It appears at her work they've done something to
disable or rather screw up the outbound RDP connections.

Now, she's no longer trying to connect, but I thought that this might be a
vulnerabilty and a malicious user could lock me out of my computer until I
get home to reset it.

Note that I have Windows Auto Update ON and therefore have all public
hotfixes continuously installed.

Is there a known denial of service issue like that and is there anything I
could do to protect my computer (short of disabling RDP access)?

 

[Matt Gibson]

Firstly, I highly doubt this is someone doing something malicious, or
something that someone can even do purposefully.

This is usually a problem with the router, either with improper MTU
settings, or just a flaky router period.

Try replacing the router with another (or just flashing the firmware), and
see if your problems go away.

Matt Gibson - GSEC