A large hedge fund was the victim of a complex cyber attack in late 2013 that ended up costing the organization millions of dollars.

In an interview with CNBC, Paul Henninger, global product director at security firm BAE Systems Applied Intelligence, gave insight on the incident, which had not been previously disclosed.

Attackers set their sights on the hedge fund's trade order entry system, and after successfully compromising it, were able to send details surrounding their trades to anonymous offsite computers controlled by them. According to Henninger, the attack – which was mitigated by technicians at BAE – involved “technical sophistication” that the firm had not previously come across.

The name of the hedge fund has not been revealed by the security firm because it is a client.

UPDATE: A spokesperson for BAE Systems Applied Intelligence told SCMagazine.com on Thursday that the hacking incident presented to CNBC by Paul Henninger as a client case study did not actually happen. The information was presented as an actual event that occurred, when it should have been an example of a scenario.