BHO's - Browser Helper Objects - What they are and How They Can Be Dangerous

I believe it's essential that everyone be aware and know how to look over your BHOs and be able decipher the good from the bad. Slight changes to BHO code makes your spyware scanner ineffective until they can catch up with the culprits. BHO spyware is still out there and watching what you do.

 Essentially BHO's, what I will refer to them as from now on, are DLL modules loaded by Internet Explorer to help facilitate added functionality. A good example is being able to read pdf files while online is a function of a BHO DLL file that gets loaded when IE starts. You could have a BHO installed when you install a IE Toolbar, like Yahoo's or Google's toolbar.

 The problem with BHO's, like anything else that was designed for something good, is that they have unrestricted access to the IE event module, the IE program itself. Spyware is notorious for installing itself as a BHO and being granted full access to the system. Thus they can track your surfing habits or record key strokes.

BHO's were introduced back with IE 4.0 and spyware has been taking advantage of this ever since. So Microsoft responded with IE 6.0 sp2 on WinXP with a way to display all the installed BHO's, as well as all browser extensions and Active-X controls that were installed on your system. But the best way I've found to look at your BHO list is through a freeware program BHODemon. Below is a screen pic of what you can expected to see.

Below, as you can see, I was unsure of what yt.dll was. So I clicked the details button and it revealed to me that it was my Yahoo toolbar. So yes it was safe because I do have the Yahoo toolbar installed. If you find one that you are not familiar with than I would uninstall it or just disable it temporarily until you find out its purpose.

A good tool for dealing with spyware and or BHO's in general is HiJackThis by Black Viper or Spybot.

Another tool put out by Microsoft is the Add-On Manager. You can access the tool from IE as shown below.

This was introduced with WinXP SP2, IE 6.0

Here's what it looks like when opened. There's the Yahoo toolbar and the option to disable it.

A lot of times if you experience issues with IE it might just be just a corrupted BHO. You could try updating the BHO, per the Updates button, if active. Or simply disabling it to see if your issue disappears. This is why I like to have three or four different browsers installed on my PC at any one time. A BHO could effectively prevent you from even accessing the internet or HiJack your homepage. Every browser requires different programs or so called add-ons /  plug-ins that they use to give you added functionality. Always be aware of what plug-ins you install into any browser

you use.

Did you know that BHOs are not stopped by personal firewalls, because they are seen by the firewall as your browser itself? Some exploits of this technology search all pages you view in IE and replace banner advertisements with other ads. So suffice it to say that you need to be aware of the BHO's or plugins you install. Your essentially granting that piece of code unrestricted access to your system.