The fix was excluded from Microsoft’s monthly patch batch and requires users to run an authentication routine, designed to check their copy of Windows is licensed, before they can download and install it.
Because of the way that some dialing software configures routing tables, Windows Firewall in Windows XP SP2 can sometimes interpret the whole Internet to be a local subnet, Microsoft wrote. This can let anyone on the Internet access the Windows Firewall exceptions.
When the My network (subnet) only option is enabled, it is automatically selected for file and print sharing, Microsoft wrote in its advisory. Therefore, your shared drives can be unexpectedly revealed on the Internet when you use a dial-up connection.
The problem is rated Critical, which usually means a worm could be written to exploit it. The problem was publicly acknowledged by Microsoft as long ago as September. The company offered a workaround at that time.
It is not an update that addresses a software code vulnerability, and therefore does not have a security bulletin associated with it, a spokesperson said in a statement attributed to Gary Schare, product director for Windows Client.
