Government officials have yet to confirm the identity of the attackers, though Chinese hackers are being flagged as suspects.
A massive Chinese-based hacker attack on Canadian federal government agencies late in 2010 was aimed at uncovering information about the takeover bid for Potash Corp. of Saskatchewan.
China is denying a U.S. congressional committee's claim that hackers interfered with two government satellites.
Months after hackers invaded the computer systems of at least three federal government institutions employees are still feeling the effects.
