Updated at 6:15 p.m.
In the days leading up to the election, Donald Trump’s and Hillary Clinton’s campaign websites saw a series of brief surges in traffic. The visitors didn’t appear to be undecided voters—or human at all. Instead, according to cybersecurity researchers at Flashpoint, the hits came from a horde of internet-connected devices, controlled by a strain of the same malware that was used in the coordinated attack that slowed the internet up and down the East Coast of the United States last month.
The spikes in traffic were amateur attempts at launching denial-of-service attacks against the candidates’ websites, the researchers concluded. By sending a stampede of fake visitors through the front door in a very short amount of time, the attackers tried to bring down the campaign websites. They didn’t succeed, though: Neither website experienced an outage.
Flashpoint detected four attacks in the 48 hours before election day. All four of them targeted the donation page on Trump’s website, and the last one also took aim at Clinton’s. Each lasted only 30 seconds. There’s no evidence the attacks were coordinated—in fact, they were probably launched by competitors, according to John Costello, a senior analyst at Flashpoint.