File-sharing technology is a popular way for users to exchange, or
"share," files. However, using this technology makes you susceptible
to risks such as infection, attack, or exposure of personal
What is file sharing?
File sharing involves using technology that allows internet users to
share files that are housed on their individual computers.
Peer-to-peer (P2P) applications, such as those used to share music
files, are some of the most common forms of file-sharing technology.
However, P2P applications introduce security risks that may put your
information or your computer in jeopardy.
What risks does file-sharing technology introduce?
- Installation of malicious code - When you use P2P applications, it
is difficult, if not impossible, to verify that the source of the
files is trustworthy. These applications are often used by
attackers to transmit malicious code. Attackers may incorporate
spyware, viruses, Trojan horses, or worms into the files. When you
download the files, your computer becomes infected (see
Recognizing and Avoiding Spyware and Recovering from Viruses, Worms, and Trojan Horses for more information).
- Exposure of sensitive or personal information - By using P2P
applications, you may be giving other users access to personal
information. Whether it's because certain directories are
accessible or because you provide personal information to what you
believe to be a trusted person or organization, unauthorized
people may be able to access your financial or medical data,
personal documents, sensitive corporate information, or other
personal information. Once information has been exposed to
unauthorized people, it's difficult to know how many people have
accessed it. The availability of this information may increase
your risk of identity theft (see Protecting Your Privacy and
Avoiding Social Engineering and Phishing Attacks for more
- Susceptibility to attack - Some P2P applications may ask you to
open certain ports on your firewall to transmit the files.
However, opening some of these ports may give attackers access to
your computer or enable them to attack your computer by taking
advantage of any vulnerabilities that may exist in the P2P
application. There are some P2P applications that can modify and
penetrate firewalls themselves, without your knowledge.
- Denial of service - Downloading files causes a significant amount
of traffic over the network. This activity may reduce the
availability of certain programs on your computer or may limit
your access to the internet (see Understanding Denial-of-Service
Attacks for more information).
- Prosecution - Files shared through P2P applications may include
pirated software, copyrighted material, or pornography. If you
download these, even unknowingly, you may be faced with fines or
other legal action. If your computer is on a company network and
exposes customer information, both you and your company may be
How can you minimize these risks?
The best way to eliminate these risks is to avoid using P2P
applications. However, if you choose to use this technology, you can
follow some good security practices to minimize your risk:
- use and maintain anti-virus software - Anti-virus software
recognizes and protects your computer against most known viruses.
However, attackers are continually writing new viruses, so it is
important to keep your anti-virus software current (see
Understanding Anti-Virus Software for more information).
- install or enable a firewall - Firewalls may be able to prevent
some types of infection by blocking malicious traffic before it
can enter your computer (see Understanding Firewalls for more
information). Some operating systems actually include a firewall,
but you need to make sure it is enabled.
Author: Mindi McDowell, Brent Wrisley, Will Dormann
The above article is reproduced with the kind permission of US-CERT (United States Computer Emergency Readiness Team) and the original document may be viewed by clicking here