AT&T spokesman Michael Coe told CNET News in an e-mailed statement that a denial-of-service attack was what stemmed the temporary block of 4chan traffic and that it has since been restored. "Beginning Friday, an AT&T customer was impacted by a denial-of-service attack stemming from IP addresses connected to img.4chan.org," Coe wrote. "To prevent this attack from disrupting service for the impacted AT&T customer, and to prevent the attack from spreading to impact our other customers, AT&T temporarily blocked access to the IP addresses in question for our customers. This action was in no way related to the content at img.4chan.org; our focus was on protecting our customers from malicious traffic."
"Overnight Sunday, after we determined the denial-of-service threat no longer existed, AT&T removed the block on the IP addresses in question," the AT&T statement continued. "We will continue to monitor for denial-of-service activity and any malicious traffic to protect our customers."