"Among other things, Suncor employees have also been told in recent days not to use social media on company devices or let people tailgate behind them into an elevator."

Suncor is replacing employee computers after a cybersecurity incident last week shut down debit and credit processing at Petro-Canada gas stations across the country, among a series of other security measures at the Calgary-based company.

"Normally you wouldn't expect hardware to be compromised so fully that you need to replace everything,"