Washington ( CNN ) -- An infected flash drive put in a U.S. military laptop in 2008 set off the most significant cyberattack ever against the military and brought a turning point in cyberdefense strategy , a top defense official wrote in an article published Wednesday . Deputy Defense Secretary William J. Lynn III , in an article titled `` Defending a New Domain '' posted on Foreign Affairs magazine 's web site , said the `` previously classified incident was the most significant breach of U.S. military computers ever . '' According to Lynn , the attack served as `` an important wake-up call '' that led to a new Pentagon counterattack strategy dubbed Operation Buckshot . `` An enormous amount of foundational work remains , but the U.S. government has begun putting in place various initiatives to defend the United States in the digital age , '' Lynn 's article said . The attack started with the infected laptop at a U.S. base in the Middle East , according to Lynn . `` The flash drive 's malicious computer code , placed there by a foreign intelligence agency , uploaded itself onto a network run by the U.S. Central Command , '' his article said . `` That code spread undetected on both classified and unclassified systems , establishing what amounted to a digital beachhead , from which data could be transferred to servers under foreign control . '' He continued : `` It was a network administrator 's worst fear : a rogue program operating silently , poised to deliver operational plans into the hands of an unknown adversary . '' Lynn 's article provided no details on specific files lost or stolen in the attack , which he called one of countless attempts to intrude into U.S. military networks . Others also have succeeded , he said , with adversaries acquiring `` thousands of files from U.S. networks and from the networks of U.S. allies and industry partners , including weapons blueprints , operational plans , and surveillance data . '' In response , he wrote , the Pentagon has built layered defenses around military networks and launched the new U.S. Cyber Command to `` integrate cyberdefense operations across the military . '' `` The Pentagon is now working with the Department of Homeland Security to protect government networks and critical infrastructure and with the United States ' closest allies to expand these defenses internationally , '' Lynn wrote .
Top Secret official details previously classified information . Infected flash drive in laptop infiltrated into IT systems . In Cyber Command , other steps are part of the plan .