OSNews

Application firewalls like zonealarm are not as useful as they once were. These products can only ask you whether or not you want to allow a particular application, as identified by the process image name, to access the internet.

Lots of newer spyware will not run in thier own process space. Instead a newer spyware application will install its bots and internet connection threads in an existing process.

Here is an example:
A spyware application, lets call it nasty.exe, starts up and drops a file containing its spyware code onto the disk. Lets say this file is called spy.dll. Next nasty.exe opens a handle to a well known process that people expect to access the internet, like iexplore.exe. Nasty.exe uses a standard process injection technique (you don't need to be administrator to do this) to get the running copy of iexplore to load spy.dll into a new thread. Now the spyware code is running as a new thread in iexplore.exe.

In this scenario, zonealarm is totally useless. All access to the internet from the spyware code will look like it comes from iexplore.exe, which has proabably been set to OK by the user.

This sort of anti-detection is rather easy to do, and becomming quite common. The more common this gets, the less useful products like zonealarm become.

At this point, I don't even bother with them.