(CNN) -- Internet users around the globe were facing slowed down service thanks to what's being called the biggest cyberattack in history.
The prolonged denial-of-service assault is targeting Spamhaus, a European spam-fighting group that has gone after a data-storage company that offers to host any content "except child porn and anything related to terrorism."
The organization has been in a long-running feud with CyberBunker, which it says spammers use as a host to spray junk mail across the Web. Web security firm CloudFlare said Spamhaus contacted it last week, saying it had been hit with an attack big enough to knock its site offline.
Security experts say the attack uses more sophisticated techniques than most DDOS (distributed denial of service) attacks and targets the Web's infrastructure, which has led to other sites performing slowly.
"These things are essentially like nuclear bombs," Matthew Prince, CloudFlare's CEO, told the New York Times. "It's so easy to cause so much damage."
The Spamhaus Project is a nonprofit organization that patrols the Internet for spammers and publishes a list of Web servers those spammers use. According to Prince, the group may be responsible for up to 80% of all spam that gets blocked. This month, the group added CyberBunker to its blacklist.
"While we don't know who was behind this attack, Spamhaus has made plenty of enemies over the years," Prince wrote in a blog post. "Spammers aren't always the most lovable of individuals and Spamhaus has been threatened, sued, and DDoSed regularly."
By DDoS he is referring to a denial of service attack, in which computers flood a website with requests, overwhelming its servers and causing it to crash or become inaccessible for many users.
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