Credit: REUTERS/Kevin Lamarque North Korea’s Internet was restored Tuesday local time, after an outage that lasted for 9 hours and 31 minutes, according to a company that monitors Internet performance.Dyn Research had earlier reported that the four networks in the country were down.The cause of the outage is not known, but led to speculation that the U.S. may have retaliated for North Korea’s alleged role in the hack of Sony Pictures in late November.The U.S. Federal Bureau of Investigation said Friday it held North Korea responsible for the attack, which came ahead of the planned release by Sony of a comedy movie about a plot to assassinate the country’s leader Kim Jong Un. President Barack Obama said soon after that at a news conference that the U.S. would respond proportionally to the attack “in a place and time and manner we choose.”“All four North Korean prefixes have been restored to service at 01:46 UTC, after a national outage of nine and a half hours. Traffic is routing through China Unicom, just as before,” Dyn said in an update. It also tweeted that North Korean-hosted websites had returned. The company had earlier reported that North Korea went off the Internet at 16:15 UTC after more than 24 hours of sustained weekend instability, but said such long outages were not without precedent in the country.“A long pattern of up-and-down connectivity, followed by a total outage, seems consistent with a fragile network under external attack,” wrote Jim Cowie, Dyn’s chief scientist in a blog post. “But it’s also consistent with more common causes, such as power problems.”North Korea is dependent on a single international provider, China Unicom.John Ribeiro covers outsourcing and general technology breaking news from India for The IDG News Service. Follow John on Twitter at @Johnribeiro. John’s e-mail address is john_ribeiro@idg.com Related content news analysis LogoFAIL attack can inject malware in the firmware of many computers Researchers have shown how attackers can deliver malicious code into the UEFI of many PCs though BIOS splash screen graphics. By Lucian Constantin Dec 08, 2023 8 mins Malware Malware Cybercrime news Google expands minimum security guidelines for third-party vendors Google's updated Minimum Viable Secure Product (MVSP) program offers advice for working with researchers and warns against vendors charging extra for basic security features. By John P. Mello Jr. Dec 08, 2023 4 mins Application Security Supply Chain Supply Chain news New CISO appointments 2023 Keep up with news of CSO, CISO, and other senior security executive appointments. By CSO Staff Dec 08, 2023 28 mins CSO and CISO CSO and CISO CSO and CISO news Top cybersecurity product news of the week New product and service announcements from Coro, Descope, Genetec, Varonis, Cloudbrink, Databarracks, and Security Journey By CSO staff Dec 07, 2023 22 mins Generative AI Security Podcasts Videos Resources Events SUBSCRIBE TO OUR NEWSLETTER From our editors straight to your inbox Get started by entering your email address below. Please enter a valid email address Subscribe