(Reuters) - A hack at global accounting firm Deloitte [DLTE.UL] disclosed in September compromised a server with emails of some 350 clients, including U.S. government agencies and large corporations, the Guardian reported on Tuesday, citing unnamed sources. Deloitte disputed the story, saying  very few  clients were affected  in a statement emailed to Reuters.  We take any attack on our systems very seriously,  the statement said.  We are confident that we know what information was targeted and what the hacker actually did.  
Deloitte cyber attack affected up to 350 clients: Guardian