WASHINGTON (CNN) -- A computer worm named "Welchia" contaminated part of the U.S. State Department's computer network on Tuesday, according to a senior State Department official.
The worm did not affect the network's classified files.
At noon, the department shut down the network's unclassified portion for nine hours, in order to protect the system and eradicate the computer worm.
That shut-down affected the network's "Consular Check System" -- used to perform background and criminal checks on those seeking U.S. visas.
As a result, the U.S. government temporarily suspended its worldwide visa processing system for nine hours, and no visas were issued during that time.
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http://www.cnn.com/2003/TECH/internet/09/24/state.dept.virus/