Industry sources say a foreign government is the most likely origin of the attack, although no country or organisation has been named.
An IMF spokesman confirmed the attack has taken place and said the organisation is “investigating it and the fund is completely functional”.
It has not confirmed what data was compromised by the hackers. It is suspected malicious software was purposefully loaded onto an IMF computer, from which the virus was allowed to spread. The data could have been loaded onto the target PC through a “spear phishing” attack, when a highly targeted email, or a duplicate of a genuine email, is sent to an individual.
Any confirmation of a country’s involvement would become a major diplomatic incident. Earlier this month President Barack Obama said any state-backed cyber attack on a US organisation would be treated as a military strike and responded to as such. Chinese hackers have been suspected of being behind several recent data theft attempts including one aimed at the email accounts of US officials.