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Only after the next intrusion, when Volexity managed to get more complete logs of the hackers’ traffic, did its analysts solve the mystery: The company found that the hijacked machine which the hackers were using to dig around in its customer’s systems was leaking the name of the domain on which it was hosted—in fact, the name of another organization just across the road. “At that point, it was 100 percent clear where it was coming from,” Adair says. “It’s not a car in the street. It’s the building next door.”
With the cooperation of that neighbor, Volexity investigated that second organization’s network and found that a certain laptop was the source of the street-jumping Wi-Fi intrusion. The hackers had penetrated that device, which was plugged into a dock connected to the local network via Ethernet, and then switched on its Wi-Fi, allowing it to act as a radio-based relay into the target network. Volexity found that, to break into that target’s Wi-Fi, the hackers had used credentials they’d somehow obtained online but had apparently been unable to exploit elsewhere, likely due to two-factor authentication.
Volexity eventually tracked the hackers on that second network to two possible points of intrusion. The hackers appeared to have compromised a VPN appliance owned by the other organization. But they had also broken into the organization’s Wi-Fi from another network’s devices in the same building, suggesting that the hackers may have daisy-chained as many as three networks via Wi-Fi to reach their final target. “Who knows how many devices or networks they compromised and were doing this on,” says Adair.
In fact, even after Volexity evicted the hackers from their customer’s network, the hackers tried again that spring to break in via Wi-Fi, this time attempting to access resources that were shared on the guest Wi-Fi network. “These guys were super persistent,” says Adair. He says that Volexity was able to detect this next breach attempt, however, and quickly lock out the intruders.
Volexity had presumed early on in its investigation that the hackers were Russian in origin due to their targeting of individual staffers at the customer organization focused on Ukraine. Then in April, fully two years after the original intrusion, Microsoft warned of a vulnerability in Windows’ print spooler that had been used by Russia’s APT28 hacker group—Microsoft refers to the group as Forest Blizzard—to gain administrative privileges on target machines. Remnants left behind on the very first computer Volexity had analyzed in the Wi-Fi-based breach of its customer exactly matched that technique. “It was an exact one-to-one match,” Adair says.