New York (CNN) The Democratic National Committee's head of cybersecurity is warning presidential primary candidates that the best time for hackers to target their campaigns is right now -- in the early days of the cycle.

"The best time to attack is before a (candidate's campaign) has their sea legs, before they've put a security plan in place," Bob Lord, the DNC's chief security officer, told CNN.

Lord also warned that those who have not yet announced they are running are also at risk.

"The trick is the adversaries are already at work, whether a candidate has announced or not. They know the list of plausible candidates; so does everybody else," he said.

Lord said the DNC is available to support all Democratic candidates. A former Silicon Valley executive, Lord was hired by the DNC last year in an attempt to improve the Democrats' cybersecurity, after the DNC, the Democratic Congressional Campaign Committee and Hillary Clinton's campaign staff were hacked in 2016.

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