Michael Brophy is CEO of Certification Europe and CEO of Quarters Quarters in Ireland. Brophy says the biggest threat to your informations security is the person sitting beside you, maybe not directly beside you. The biggest threat is the staff that have not been trained to handle data properly are the number one source of data breaches. In June 2012 Islington Council in the UK responded to a freedom of information request by supplying 3 excel sheets with pivot tables the fulfilled the request but also gave a copy of the raw data from which these pivot tables were derived. This data table was hidden from view but still accessible to someone with training.”]
Source: https://informationsecuritybuzz.com/articles/biggest-threat-info-security-sitting-office-right-now/