Investigation into the South American grid failure centered on Argentina proceeds, but remains in its early stages, and no cause has been publicly identified, according to AFP and other sources. The blackout is thought to have cascaded from a local failure. "Operational and design errors" are thought to be at fault. Officials in Argentina say, according to the AP, that while a cyberattack is a possibility, that seems unlikely.

The BBC summarizes reports of US-staged malware in Russia's power grid, presumably held there for retaliation against future Russian cyberattacks on US targets. The reports are unconfirmed publicly and at least partially denied by the US. TASS says Russia regards cyberwar with the US as a "hypothetical possibility," that it's accustomed to US misbehavior, and that it's quite capable of protecting its grid. Lawfare has a useful account of how the laws of armed conflict might apply to what would appear to be a long-running, low-level conflict in cyberspace that many think has the potential to produce kinetic effects.

Iran, without providing much detail, tells Reuters that Tehran has detected and thwarted a US cyber-espionage campaign.

ISIS, from its diaspora in cyberspace, is said to be expressing an interest in protecting its adherents from BlueKeep exploits. Homeland Security Today says the Electronic Horizon Foundation, an ISIS help desk, is warning about the risk of BlueKeep-based attacks. It's not just ISIS that's concerned about BlueKeep: TechCrunch reports that the US Department of Homeland Security has developed a remote-code-execution proof-of-concept exploiting the bug.