The Department of Homeland Security is seeing an increase in attacks on election databases in the run up to the midterm elections but has yet to identify who is behind the attempted hacks.
"We are aware of a growing volume of cyber activity targeting election infrastructure in 2018," the department's Cyber Mission Center said in an intelligence assessment issued last week and obtained by NBC News. "Numerous actors are regularly targeting election infrastructure, likely for different purposes, including to cause disruptive effects, steal sensitive data, and undermine confidence in the election."
The assessment said the federal government does not know who is behind the attacks, but it said all potential intrusions were either prevented or mitigated.
The techniques used by the hackers are available to nation-state and non-state hackers alike, DHS said, including malicious e-mails that appear to be legitimate and denial of service attacks. The attempted hacks have been intensifying and were detected as recently as early October.
For example, the assessment said, three different methods were used in late August in an attempt to get access to Vermont's online voter registration database, but they were unsuccessful.
Vermont's Secretary of State Jim Condos says his state's voter registration list is backed up every day and easily could be restored should someone get through.
As for attempts by foreign governments to influence the U.S. political environment, the intelligence bulletin said Russia and China remain active, though in different ways. Russia attempts to spread disinformation with hackers posing as Americans, while China is engaged in more conventional propaganda efforts.
Homeland Security Secretary Kirstjen Nielsen told a Senate hearing last week that China "is exerting unprecedented effort to influence American opinion." But she said the US not seen "any Chinese attempts to compromise election infrastructure."
Without yet identifying who is behind the recent increase in activity, DHS continues to insist Russia shows no signs of attacking voting systems the way it did in 21 states in 2016.
"We currently have no indication that a foreign adversary intends to disrupt our election infrastructure," Nielsen said earlier this month at a cybersecurity summit hosted by The Washington Post.
DHS finds increasing attempts to hack U.S. election systems ahead of midterms (NBC News)