The U.S. Federal Bureau of Investigation obtained court approval to access hundreds of vulnerable computers across the country, Vice reports. Malicious web shells left by hackers who had previously compromised Microsoft Exchange Server software systems were removed to prevent additional access. A Department of Justice announcement said the FBI “removed one early hacking group’s remaining web shells, which could have been used to maintain and escalate persistent, unauthorized access to U.S. networks.” The FBI is attempting to notify individuals whose computers were impacted.