Leading technology companies said that
a monthslong breach of corporate and
government networks was so sophisticated,
focused and labor-intensive that a nation had
to be behind it, with all the evidence pointing
to Russia.
In the first congressional hearing on the breach,
representatives of technology companies
involved in the response described a hack of
almost breathtaking precision, ambition and
scope. The perpetrators stealthily scooped up
specific emails and documents on a target list
from the U.S. and other countries.