The Revenue Canada Agency says online services may resume on the weekend. The CRA has been denying access to its electronic services because of security concerns. Revenue Minister Kerry-Lynne Findlay says it’s a precautionary measure after the Heartblead virus was found on the agency’s servers. Experts say this security threat is serious, because it remained undiscovered for two years, until it was finally found last Friday. Passwords, credit cards and other sensitive data are all at risk.