Tokyo-based cybersecurity firm Trend Micro says it discovered four phony Web domain names that were very similar to the domain names of the Macron campaign -- presumably to try to trick careless campaign workers into accidentally compromising their email accounts. For example, a fake domain called mail-en-marche.fr was set up on April 12. Macron's party is En Marche!
The firm was unable to tell whether any campaign staffers actually fell into any traps, or whether any campaign materials were compromised.
Macron's digital campaign manager, Mounir Mahjoubi, confirmed there had been attempted hacks, but said they weren't successful.
"These are usual cyberattack tactics. We have set up a security team and every member of the staff is trained to report these attempts," he told CNN, assuring no party supporters' information had been compromised.
"No sensitive data ever leaked from our apparatus."
A French official told CNN that French intelligence services are warning campaigns to take steps to prevent being targeted by hackers.
Macron, a centrist candidate, won the first round of the French Presidential election
Sunday, taking home 24.01% of the vote.
He will face off on May 7 against anti-immigrant, anti-EU candidate Marine Le Pen, who came second with 21.3%, beating establishment candidates from France's two largest political parties.
Hard to determine hacker's identity
Feike Hacquebord with Trend Micro told CNN he could not say whether the hackers were Russian. But he said the M.O. was the similar to that of the DNC hackers -- who US intelligence officials say are linked to Russian intelligence.
Hacking culprits can be difficult to track back and identify with certainty. But cybersecurity experts say French institutions have previously been targeted by hackers with ties to Russia. For example, when the broadcaster TV5 Monde was hacked in 2015, researchers at cybersecurity firm FireEye said it was carried out by Russian-backed hackers from the Russian-backed unit APT28.
"Russian intelligence have certainly been hacking inside France, and will continue to do so," said Columbia University's Jason Healey. "The attacks that Russia used against the US -- of getting hold of embarrassing information and releasing it -- I'd say the French are very open to such things."
Russian President Vladimir Putin has denied any interest in interfering with the elections in France.
Kremlin spokesman Dmitry Peskov on Monday also brushed off the allegations, which have been circulating for weeks.
"All this is a reminder of the accusations that were heard from Washington just recently and that have remained unconfirmed to this day, which does no credit to those who made them," Peskov told state-run media TASS.
He also denied suggestions that Moscow would be unhappy with a Macron win, saying the allegations were "utterly erroneous" and "primitive."
But analysts say Putin would have good reason to favor conservative nationalist Marine Le Pen over centrist Macron in the upcoming runoff election.
"Le Pen has been very open about her desire to have better relations with Russia, she's an outspoken opponent of sanctions [against Russia], and she's interested in taking France outside of NATO," said Will Pomeranz at the Woodrow Wilson Center in Washington. "She has a very populist right-wing message that plays to Putin's narratives -- it undermines Western institutions."
Le Pen visited Moscow a month ago to meet with Putin, at a time when other Western candidates would not want to be seen shaking hands with him.
Former Asst. Sec. of State David J. Kramer, now with the McCain Institute in Washington, says the two also have a number of things in common: a focus on national sovereignty, a distrust for international institutions, a keen focus on fighting Islamic terrorism, an embrace of traditional values and a vigorous style.
"They share this desire for strong leadership not encumbered by checks and balances. They want to get things done, go after common enemies," he said.