Denial of Service attacks aren't technically "hacks," since they can be done without breaking into any systems. Typically, DoS attacks overwhelm a website's servers by flooding them with requests. That makes websites unreachable or unresponsive.
To bring down bigger sites, attackers will sometimes use botnets, or large numbers of infected computers, to send requests all at once. There's not much that Web companies can do to prevent that kind of attack except to get more servers.
"DoS attacks are very difficult to defend against," said Paul Asadoorian, CEO of security consultancy PaulDotCom Enterprises. "But attackers are not stealing any information when they do a DoS."
Large, organized crime syndicates have been launching sophisticated attacks for decades.
|How Silicon Valley is dealing with mental illness|
|4 takeaways from Janet Yellen's testimony|
|China is on a massive gold buying spree|
|Mark Zuckerberg reacts to board member's India comments|
|Twitter is losing customers and its stock is falling|