SecurityWeek reported on October 12 that Canonical, the company behind Ubuntu, had its main websites disrupted last week. On October 8, Canonical said on the Ubuntu Discourse forum that the sites faced a sustained DDoS attack. That means a flood of traffic from many machines that blocks real visitors. OMG! Ubuntu listed the affected sites: ubuntu.com, canonical.com, the Ubuntu blog, the developer site, and the security advisory pages and API. Canonical said on October 9 that most services were reachable again. OMG! Ubuntu put the downtime at a little over four hours.
SecurityWeek said Canonical has not shared how large the attack was or where it came from. No one appears to have claimed it. OMG! Ubuntu said Launchpad and the Snap Store did not appear to be affected. In late April, a more disruptive attack took down services including those two, and some users could not install Ubuntu updates, SecurityWeek reported. A hacktivist group, the 313 Team, claimed that attack. Whether the two are linked is unclear.
The advisory API went down together with the company's blog and home pages. Scanners and build jobs often pull advisory lists from feeds like this to decide what needs patching. A tool that fails open carries on and may report nothing wrong. One that fails closed stops, so a build or patch run can stall. The sources do not say any tool was affected.