In 2003, prior to the country's official accession to NATO, Estonia proposed the creation of a Centre of Excellence. The 2006 Riga summit listed possible cyber attacks among the asymmetric threats to the common security and acknowledged the need for programs to protect information systems over the long term. The cyber attacks on Estonia in 2007 highlighted for the first time the potential vulnerability of any NATO countries, their institutions and societies, and even NATO itself to disruption or penetration of their information and communications systems.