The Internet has largely recovered from Friday's very large denial-of-service attacks. Arriving in several waves throughout the day, the attacks produced outages mostly in the United States, Western Europe, and Australia. DNS provider Dyn was the central point of attack, although Dyn itself may not have been the ultimate target. The effect of the attacks cascaded through many popular sites, rendering services like PayPal and Twitter temporarily inaccessible.
This DDoS attack, called by many the largest on record, follows the template established by the September 20 attacks against KrebsOnSecurity, in which the Mirai Trojan herded a large number of insecure Internet-of-things devices into a botnet that flooded its target with more requests than the host could handle. The compromised devices include, prominently, security cameras and home routers, and it's thought that hundreds of thousands of these were used in the attack. Given that there are so many of these devices in the hands of small businesses and private users, and given that they tend to be poorly patched and protected, it's expected that mopping up the vulnerabilities could take years.
The WikiLeaks-friendly New World Hackers tweeted claims of responsibility for the attacks, but observers remain cautious about buying that attribution. It's possible this could have been hacktivism, given publication of Mirai source code in the wake of Septembers attacks. But it's also possible, as former NSA Director Keith Alexander speculated Saturday at CyCon U.S., that the operation was a test-run by Russian security services interested in establishing a disruptive capability.