What is a DOS? Think of it as blackmail or bullying. The message may vary slightly, but they all want the same thing, to scare you into paying them to fix a problem that isn't real. Below is just one example that I got on my computer just the other day.
In computing, a denial-of-service attack (DoS attack) is a cyber-attack where the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to the Internet.
I have had two people this week ask me about this and I want to share so you don't have the same thing happen to you!
Customer wrote: "Yesterday when I was on Facebook, I received the following message which also froze my screen; it said that it was from Microsoft support and that I should contact 1-888-411-9933, and mention code B2957E to fix it. Here is the message: "Windows detected ZEUS Virus, the infections detected, indicate. Some recent downloading on the computer which in turn has reacted problems on the computer. A suspicious connection was trying to access your login, banking details and tracking your internet activity. Security center and Firewall services are disabled, error code Ox8007042c. Your TCP connection was blocked by your Firewall. Your accounts may be suspended until you take an action. Your personal information may have leaked IMMEDIATE RESPONSE REQUIRED"Is this a legit case or a spam?"
ANSWER: The Windows Detected ZEUS Virus alert is shown in such a way as to trick the user into thinking their computer has crashed or that a virus has been detected on the computer. It does this to try and scare the "infected" user into calling one of the listed numbers in order to receive support. In reality, though, they will only be greeted with people who are trying to sell them unneeded support contracts and services for hundreds or dollars.
The “Windows Detected ZEUS Virus” pop-up ads are caused by a malicious program, which is typically bundled with other software that you can download for free from the Internet. Also just logging into Facebook.
This will keep you from closing your browser, but don't panic! All you need to do is follow the steps below.
Step1: Open Task Manager by right-clicking the taskbar and then clicking Start Task Manager. Alternatively to start the Windows Task Manager, you can press Ctrl+Alt+Del and click on Task Manager or simply press on Ctrl+Shift+Esc.
Step2: Scroll through the list till you see your web browser’s process and left-click on it once so it becomes highlighted. Once you have selected the browser’s process, click on the End Task button as show in the picture below.
Step3: Your browser window should now be closed. The next time you open your browser, do not allow the browser to open the last opened page.
Step4: Clear your history (all of it).
I strongly recommend also installing malwarebytes, you get a 14 days free trial and after that is very affordable I think maybe $45 a year or less and worth every penny!!
Here is another article regarding these attacks: