You may have heard of denial-of-service attacks launched against websites,
but you can also be a victim of these attacks. Denial-of-service attacks can
be difficult to distinguish from common network activity, but there are some indications that an attack is in progress.
What is a denial-of-service (DoS) attack?
In a denial-of-service (DoS) attack, an attacker attempts to prevent
legitimate users from accessing information or services. By targeting your
computer and its network connection, or the computers and network of the
sites you are trying to use, an attacker may be able to prevent you from
accessing email, websites, online accounts (banking, etc.), or other
services that rely on the affected computer.
The most common and obvious type of DoS attack occurs when an attacker
“floods” a network with information. When you type a URL for a particular
website into your browser, you are sending a request to that site’s computer
server to view the page. The server can only process a certain number of
requests at once, so if an attacker overloads the server with requests, it
can’t process your request. This is a “denial of service” because you can’t
access that site.
What is a distributed denial-of-service (DDoS) attack?
In a distributed denial-of-service (DDoS) attack, an attacker may use your
computer to attack another computer. By taking advantage of security
vulnerabilities or weaknesses, an attacker could take control of your
computer. He or she could then force your computer to send huge amounts of data to a website or send spam to particular email addresses. The attack is
“distributed” because the attacker is using multiple computers, including
yours, to launch the denial-of-service attack.
How do you know if an attack is happening?
* unusually slow network performance (opening files or accessing websites)
* unavailability of a particular website
* inability to access any website
* dramatic increase in the amount of spam you receive in your account
How do you avoid being part of the problem?
Unfortunately, there are no effective ways to prevent being the victim of a
DoS or DDoS attack, but there are steps you can take to reduce the
likelihood that an attacker will use your computer to attack other
* Install and maintain anti-virus software
* Install a firewall, and configure it to restrict traffic coming into and
leaving your computer
* Follow good security practices for distributing your email address