ON TUESDAY, A trifecta of tech companies announced that they had thwarted what appear to be significant cyber attacks from Russia and Iran. First, Microsoft CEO Brad Smith announced that the company had caught another round of phishing attacks on political groups in the United States, which it attributed to the Russian hacking group Fancy Bear. Then it was Facebook’s turn. On a call with reporters, CEO Mark Zuckerberg said his company had shut down 652 pages, accounts, and groups affiliated primarily with Iran, though some had ties to Russia. Twitter almost instantly followed suit, saying it too had taken 284 accounts offline, which appeared to have originated in Iran.