Feike Hacqueboard, a senior threat researcher with security firm Trend Micro, told ABC News that he has identified four internet domain names connected to a group called "Pawn Storm" that were used to target the French centrist's campaign with so-called phishing attacks.
"The attacks could have started [in the middle of] March and I think they went on for half of April," Hacqueboard told ABC News in a phone call from the Netherlands.
Pawn Storm is also known as Fancy Bear and APT28, among a number of other monikers. The group has been linked by several private security firms to the Russian government, and in some cases, the Russian military intelligence agency called the GRU.
For its part, Trend Micro -- as a policy -- does not point fingers at state actors for fear of interfering in the political process, Hacqueboard said. But he conceded that Pawn Storm are after targets that are of interest to the Russian government.
In addition to the DNC, the group was behind the recent cyberattacks on the Turkish parliament and Angela Merkel's party in Germany (the CDU), as well as cyberattacks on the parliaments of Montenegro and Germany, according to Hacqueboard.
“We see that the fingerprints of these attacks are the same," the researcher said. "The mode of operation is very, very similar."
A spokesman for the French government cybersecurity agency ANSSI confirmed the attacks on the Macron campaign to Reuters, but would not comment on whether Pawn Storm was behind them.
Among the group's favored attack methods, Hacqueboard said, is an attack called "phishing."
This attack method sees hackers send duplicitous emails to their targets that appear to be from legitimate institutions or organizations. The emails usually demand that the target hand over some personal information, such as a password, in order to avoid some negative outcome, such as having a social media or email account locked.
The emails appear authentic, but in reality are designed to gather personal information that hackers can then exploit to gain further access to systems.
Richard Ferrand, secretary-general of Macron's party, previously accused Russia of trying to influence the French election in a February news conference and urged the French government to take action to prevent any "foreign meddling," according to Reuters.
The French election is in full swing. A first round of votes on Sunday saw Macron and far-right candidate Marine Le Pen best nine other candidates and advance to a second round of voting that is scheduled for May 7.
Le Pen has in the past expressed support for Russia's annexation of the Crimea region from Ukraine, according to BBC News. That annexation was widely condemned by the international community.
Le Pen has also called for the European Union to lift sanctions imposed on Russia, saying that they were "counterproductive," the BBC reported.
The Macron campaign did not return ABC News' request for comment.