started staying up nights, often jittery on Red Bull, to reverse-engineer malware. He waited to get pinged that the intruders were at it again.

Months later, Wallace got the alert: From Internet Protocol addresses in Tehran, the hackers had deployed TinyZbot, a Trojan horse-style of software that the attackers used to gain backdoor access to their targets, log their keystrokes and take screen shots of their information. The hacking group, he would find, included members in the Netherlands, Canada, and the United Kingdom.

The more he followed their trail, the more nervous Wallace got. According to Cylance, the intruders had launched digital offensives that netted information about Pakistan International Airlines, the Mexican oil giant Pemex, the Israel Institute of Technology and Navy Marine Corps Intranet, a legacy network of thethere was any connection between the Iranian government and the individual hackers who Wallace traced — with the usernames parviz, Alireza, Kaj, Salman Ghazikhani and Bahman Mohebbi — is unclear.

A 'LUCRATIVE' TARGET

Cyberattacks designed to steal information are steadily growing in scope and frequency; there have been high-profile hacks of Target, eBay and federal targets such as the U.S. Office of Personnel Management. But assaults on the power grid and other critical infrastructure aim to go a step further.

Trained, well-funded adversaries can gain control of physical assets — power plants, substations and transmission equipment. With extensive control, they could knock out the electricity vital to daily life and the economy, and endanger the flow of power to mass transportation, military installations and home refrigerators.

In the summer of 2014, a