software are computer programs that attempt to identify,
neutralize or eliminate malicious software. The term "antivirus"
is used because the earliest examples were designed exclusively
to combat computer viruses; however most modern antivirus
software is now designed to combat a wide range of threats,
including worms, phishing attacks, rootkits, trojan horses
and other malware. Antivirus software typically uses two
different approaches to accomplish this:
files to look for known viruses matching definitions in
a virus dictionary, and identifying suspicious behavior
from any computer program which might indicate infection.
The second approach is called heuristic analysis. Such analysis
may include data captures, port monitoring and other methods.
commercial antivirus software uses both of these approaches,
with an emphasis on the virus dictionary approach. Some
people consider network firewalls to be a type of antivirus
software, however this is not correct.
spyware program is rarely alone on a computer: an affected
machine can rapidly be infected by many other components.
Users frequently notice unwanted behavior and degradation
of system performance. A spyware infestation can create
significant unwanted CPU activity, disk usage, and network
traffic, all of which slow the computer down. Stability
issues, such as application or system-wide crashes, are
also common. Spyware, which interferes with networking software
commonly causes difficulty connecting to the Internet.
some infections, the spyware is not even evident. Users
assume in those situations that the issues relate to hardware,
Windows installation problems, or a virus. Some owners of
badly infected systems resort to contacting technical support
experts, or even buying a new computer because the existing
system "has become too slow". Badly infected systems
may require a clean reinstallation of all their software
in order to return to full functionality.
anti-virus firms such as Symantec, McAfee and Sophos have
come later to the table, adding anti-spyware features to
their existing anti-virus products. Early on, anti-virus
firms expressed reluctance to add anti-spyware functions,
citing lawsuits brought by spyware authors against the authors
of web sites and programs which described their products
as "spyware". However, recent versions of these
major firms' home and business anti-virus products do include
anti-spyware functions, albeit treated differently from
viruses. Symantec Anti-Virus, for instance, categorizes
spyware programs as "extended threats" and now
offers real-time protection from them (as it does for viruses).
programs can combat spyware in two ways:
They can provide real time protection against the installation
of spyware software on your computer. This type of spyware
protection works the same way as that of anti-virus protection
in that the anti-spyware software scans all incoming network
data for spyware software and blocks any threats it comes
2. Anti-spyware software programs can be used solely for
detection and removal of spyware software that has already
been installed onto your computer. This type of spyware
protection is normally much easier to use and more popular.
With this spyware protection software you can schedule weekly,
daily, or monthly scans of your computer to detect and remove
any spyware software that has been installed on your computer.
This type of anti-spyware software scans the contents of
the windows registry, operating system files, and installed
programs on your computer and will provide a list of any
threats found, allowing you to choose what you want to delete
and what you want to keep.
programs inspect the contents of the Windows registry, the
operating system files, and installed programs, and remove
files and entries which match a list of known spyware components.
Real-time protection from spyware works identically to real-time
anti-virus protection: the software scans disk files at
download time, and blocks the activity of components known
to represent spyware. In some cases, it may also intercept
attempts to install start-up items or to modify browser
settings. Because many spyware and adware are installed
as a result of browser exploits or user error, using security
software (some of which are antispyware, though many are
not) to sandbox browsers can also be effective to help restrict
any damage done.
versions of anti-spyware programs focused chiefly on detection
and removal. Javacool Software's SpywareBlaster, one of
the first to offer real-time protection, blocked the installation
of ActiveX-based and other spyware programs.