The arrest came at the request of the United States, which hailed the development as a sign that patience in pursuing cybercriminals in court is rewarded.

Russian losses near Kyiv and a looming onslaught in eastern Ukraine may be a factor in the attack, a Ukrainian official said.

The allegation marks a quick turnaround for U.S. national security officials after voters reported a series of odd messages.

In a first for China-based group, FireEye said, the hackers are using malware typically reserved for spying for personal gain.

Israel's targeting of alleged Hamas hackers was the first instance of a 'kinetic' response to a cyberattack. But it wasn't a surprising outcome.

The campiagn is linked to the Luhansk People’s Republic, a group that declared independence from Ukraine in 2014.

Sources told CyberScoop that 18 companies have received the phishing emails, with another five investigating incidents that may be tied to the same attackers.