Cyberwarfare and State-Sponsored Attacks

A watershed moment for state cyberwarfare came in April 2007, when Estonia relocated a Soviet-era war memorial, the "Bronze Soldier," from central Tallinn, triggering sustained distributed denial-of-service (DDoS) attacks against Estonian government ministries, banks, and media outlets, widely attributed to Russian-linked actors though never definitively traced to the Russian state itself. The episode directly prompted NATO to establish the Cooperative Cyber Defence Centre of Excellence (CCDCOE) in Tallinn in 2008, and later produced the Tallinn Manual (2013), an influential non-binding scholarly analysis of how existing international law applies to cyber operations, expanded in the 2017 Tallinn Manual 2.0 to cover peacetime cyber incidents below the threshold of armed conflict.