Russian, Chinese and Iranian hackers have stepped up efforts to disrupt the US election by targeting the campaigns of President Donald Trump and Democratic nominee Joe Biden, a Microsoft Corp. investigation found.

Cyber-attacks have also been aimed at political parties, advocacy groups, academics and leaders in the international affairs community, according to a blog post Thursday from Tom Burt, corporate vice president of customer security and trust at Microsoft.

SKDKnickerbocker, a public affairs and political consulting firm working with Biden’s campaign, was also recently targeted in an unsuccessful hack by suspected Russian state-backed hackers, according to a Thursday report by Reuters, which said that Microsoft had alerted the firm.

The attempted hack on SKDKnickerbocker reflects a broader trend documented by Microsoft: that a Russia-based group had attacked “political campaigns, advocacy groups, parties and political consultants.”

Attempts by foreign adversaries to disrupt the Nov. 3 presidential election echo the efforts by Russia in 2016 to meddle in the campaign on Trump’s behalf. The president is trailing Biden in the 2020 race by more than 7 percentage points in a national average of polls.

The findings emerged hours after the US sanctioned Andrii Derkach, a Ukrainian lawmaker who met with Trump’s personal lawyer last year, alleging he’s a Russian agent trying to influence the 2020 election.

Microsoft’s report also came a day after a Homeland Security Department official alleged that Trump administration appointees suppressed intelligence on Russian election interference while promoting China as the prime threat.

Microsoft reported that about 200 organizations directly or indirectly tied to the US election and political organizations in Europe were affected by a Russian-operated group, called Strontium, including US-based consultants serving Republicans and Democrats. The same group was also identified in the report by Special Counsel Robert Mueller as being responsible for the attacks on the Democratic presidential campaign in 2016, according to Microsoft. Strontium is also known as APT28, or Fancy Bear.

Microsoft also reported unsuccessful cyber-attacks from Iran on people associated with the Trump campaign, and attempted attacks from China on people associated with the Biden campaign, as well as a “prominent” individual formerly associated with the Trump administration. The people who were targeted weren’t named.

The Chinese group, referred to as Zirconium, has mounted thousands of attacks from March through September on campaign officials as well as prominent academics and others in international affairs. Of those attempts, about 150 were successful breaches, but Microsoft didn’t identify the victims other than to say they weren’t associated with the presidential campaigns.

According to John Hultquist, who serves as the senior director of analysis at cybersecurity firm FireEye Inc.’s Mandiant, the recent Russian activity poses the greatest threat to the election. “It’s likely Iranian and Chinese actors targeted US campaigns to quietly collect intelligence, but APT28’s unique history raises the prospect of follow-on information operations or other devastating activity,” he said.

Microsoft’s findings echo those of US government officials.

“Our adversaries are continuously looking for vulnerable US networks to exploit, and networks associated with political organizations and campaigns are no exception,” the Federal Bureau of Investigation said in a statement on Thursday.

In August, William Evanina, head of the National Counterintelligence and Security Center, said Russia, China and Iran are trying to “use covert and overt influence measures in their attempts to sway US voters’ preferences and perspectives, shift US policies, increase discord in the United States, and undermine the American people’s confidence in our democratic process.” And on Wednesday, Chad Wolf, acting secretary of the Department of Homeland Security, said “the governments of China, Iran and Russia target our election systems, each with its own separate and nefarious motives and tactics.”

“Protecting our elections is a team effort with the federal government and the private sector joining together to thwart foreign malign actors,” Wolf said in a Thursday statement about the Microsoft findings.

‘Stepped up’

The recent attacks reveal that “foreign activity groups have stepped up their efforts targeting the 2020 election,” according to Microsoft. “What we’ve seen is consistent with previous attack patterns that not only target candidates and campaign staffers but also those who they consult on key issues.”

The majority of attacks were detected and stopped by security tools built into Microsoft’s software, Burt said.

Foreign groups used tactics including rotating IP addresses to disguise attacks, web bugs planted in purchased domain names and phishing, in an effort to harvest login credentials and gain information on targeted individuals and organizations. Phishing attacks can be for routine espionage against campaigns or, in some cases, to conduct hack and leak operations — a key feature in Russia’s campaign to help Trump and hurt Hillary Clinton in 2016.

Disinformation experts are on high alert for strategic leaks of real or fabricated documents in the weeks ahead of election day, as a foreign influence tactic that could significantly harm a candidate’s chances, particularly if there isn’t enough time for them to adequately respond.

On Thursday, the Department of Homeland Security’s Cybersecurity and Infrastructure Security Agency released public guidance for combating email attacks related the election. “CISA strongly recommends elections-related individuals and organizations to prioritize the protection of email accounts and systems,” the agency said.

“We disclose attacks like these because we believe it’s important the world knows about threats to democratic processes,” Microsoft’s Burt said. He also said more federal funding is needed in the US so states can better protect their election infrastructure.

The Office of the Director of National Intelligence said in a statement Thursday that the “private sector plays a crucial role” in safeguarding elections and national security. “We welcome their assistance and will continue partnering with them to combat foreign efforts to target political candidates, campaigns and others involved in the US elections,” according to the statement.