What is a DoS attack?
Definition
A denial of service (DoS) attack stops legitimate users from reaching a website, service or system, or slows it down, usually by overwhelming it with traffic or requests.
- Category
- Attacks
- Also called
- DoS, denial-of-service attack
- Last updated
NIST defines denial of service as the prevention of authorized access to resources or the delaying of time-critical operations. Time-critical can mean milliseconds or hours, depending on the service.
In plain terms: someone makes a website, app, game server or network so busy or so broken that real users can't get in. Nothing has to be stolen. The point is the outage.
A concrete example
A small online shop gets hit during a sale. A flood of junk requests fills its server's capacity, and customers see error pages or a site that never loads. The shop is down until the traffic stops or gets filtered.
DoS vs. DDoS
A DoS attack comes from one source. A distributed denial of service (DDoS) attack uses many devices at once, which makes it harder to block, because there's no single address to cut off.
Does it affect you personally?
Usually indirectly: a service you rely on goes down, such as a bank, a game or a store. A DoS attack doesn't normally expose your personal data by itself. It can be used as a distraction or as pressure, though, so it's worth watching for unusual account activity if a service you use is having trouble.
How to protect yourself
- 1
Don't panic-reset passwords on a hunch
An outage alone isn't a breach. Check the company's official status page or social account before you act on emails about it.
- 2
Be wary of "we're under attack" messages
Scammers use outages as a cover story to ask for logins or payments. Go to the company's site directly instead of using links in a message.
- 3
Keep your own devices updated
Compromised devices can be used to send attack traffic without their owners noticing. Updates and unique passwords on routers and smart devices reduce the risk.
- 4
Run a service? Talk to your host
If your own site or game server is being hit, contact your hosting provider and ask what traffic filtering they offer.
See where your personal data is exposed
Serus finds it on data brokers and people-search sites and removes it.
Frequently asked
What is the difference between DoS and DDoS?
DoS comes from a single source. DDoS is distributed: the traffic comes from many devices at the same time, which makes it harder to block.
Does a DoS attack steal data?
By NIST's definition, a DoS attack prevents access or delays operations. It isn't about taking data, although attackers may use it alongside other attacks.
Can a DoS attack hurt my home network?
It can slow or cut off your connection if your own address is targeted. Restarting your router may get you a new address from your provider; if it keeps happening, contact them.
Sources
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