NSA data may have been dumped in second leak

The group responsible for publishing National Security Agency data over the summer released hundreds of new files on Monday, exposing domains and Internet protocol addresses that could reveal who the agency has targeted over the last several years.

"The Shadow Brokers is having special trick or treat for Amerikanskis tonight," the group taking credit for the leak wrote in a blog post on Medium.

The information contains more than 300 folders with files allegedly taken from the Equation Group, a group that has been linked to attacks on foreign governments and thought to be representative of the NSA's elite Tailored Access Operations unit.

The files reportedly include 306 domain names and 352 IP addresses based in countries including Russia, China, and India, meaning the NSA used hardware based in those countries to mask its operations. The information provides a roadmap for victims to trace cyberattacks back to the agency.

The group first published information from the Equation Group in August, and said it was seeking as much as $500 million to sell the rest of what it held. Experts quickly noted the data dated back to October 2013, making it largely obsolete, and speculated the Russian government was simply using the group as a front to embarrass the American intelligence community.