Spyware symptoms and characteristics
It is often difficult to determine if your computer has been infected by spyware. These programs are designed to run in the background and draw as little attention as possible. However, if you notice any of these symptoms, it might be time to examine your computer more thoroughly.
Slower Response Time
Most computer users are very in tune with how quick or slow their machines run. So, if you notice that your computer suddenly becomes much slower when opening programs, crashes and/or freezes more often or has difficulty accessing the internet, spyware or other malware may be the culprits.
Though spyware is designed to hide itself on a computer system, it does use processing power and your network connection to carry out its tasks - both of which will slow down your computer's performance. However, the differences may not be noticeable until there are several spyware programs at work on your computer. Any sudden change in system performance is usually a signal that something is wrong.
Offline or Inappropriate Pop-ups
If you've noticed that you are receiving pop-up advertisements even when you are not online or viewing a webpage, it is possible that your computer has been infected with a type of spyware which contains adware. Though most adware is used by legitimate companies, some versions have spyware features built-in and are therefore classified as a type of spyware. These adware programs are not only annoying but can cause serious problems for both your network and your computer. Some of these applications have been known to crash computers by flooding them with hundreds of simultaneously opening windows.
Another indication of adware/spyware infection is if you begin receiving inappropriate pop-ups in context to the website you are currently viewing. For example, if you are reading the online version of a reputable newspaper and begin seeing pop-up ads for porn sites, this can alert you that someone else is serving your advertisements.
Browser or Desktop Changes
Many spyware programs attach to and/or alter your internet browser, especially Internet Explorer. These programs are often referred to as browser hijackers.
Fortunately, of the various spyware available, these are the easiest to detect. If you have unknowingly installed this type of spyware on your machine you may notice that your homepage has been changed, you have new bookmarks, a new tool bar has been added to your browser, new icons have been added to your desktop or when you perform an internet search, your default search provider has been changed.
Some spyware applications will also redirect you to specific websites and change your hosts file. Though these programs are more visible, they can be notoriously difficult to uninstall and frequently require specialist removal tools.
Bounced Email
Spyware is sometimes bundled with trojans. This type of spyware is frequently used for key logging and password theft. However, the associated trojans are more commonly used for sending spam emails. If you notice a sudden and dramatic increase in the number of bounced emails you receive, especially if they are addressed to people you have not emailed or don't know, this may be an indication that you have a trojan and associated spyware installed on your machine.
These programs are often spread through the spam that they deliver and can therefore be avoided by not clicking on the links contained in the junk email.
Remote Access
Another hazard of spyware is its ability to expose the host machine's security vulnerabilities, allowing remote users to access the machine at will. These spyware applications are normally grouped with trojans, specifically remote access trojans (RATs). If your computer hard drive runs non-stop and your network data transfer is active even when you are not using the computer, there is a possibility that RATs are to blame and the computer should have full systems scans done with both an antivirus as well as anti-malware programs.
Rogue Software
Not all anti-malware creators are ethical. If you've recently installed a new anti-malware or anti-spyware program and have noticed that your machine performance has been altered or you are receiving pop-up ads when you are not online, you may have installed one of the many bogus anti-spyware applications that actually load spyware and adware onto the victim's computer. This type of spyware is usually found in pop-up ads pretending to be 'security alerts'. When the user clicks on the pop-up, sometimes even when trying to close the window, it will load the spyware and/or trojan onto the computer.