UPNP is code designed for trying to exploit the UPnP vulnerability in Windows XP/Me/98 computers.
Some worms spread through the Internet. In order to do so, they generate several random IP addresses. Then, these worms send UPNP to these IP addresses.
If the targeted computer is not properly updated, when it receives UPNP, these worms will be downloaded and executed.
Another possible scenario would be the creation of a program that would scan IP addresses. This program should detect the vulnerable IPs in order to install other malware, such as Trojans or backdoors, in the targeted computers.
Panda Security detects the code necessary for attempting to exploit the UPnP vulnerability as UPNP, thus warning users on a network traffic increase associated to this threat and preventing them from being affected.
If you have a Windows XP/Me/98 computer, it is highly recommendable that you download the security patch from Microsoft's web site, by clicking here.