The release, the fourth one in the WikiLeaks series dubbed Spy Files, is made mostly of files that were leaked by an unidentified hacker who breached FinFisher's corporate network in August.

See also: Hackers Build Spy Tools From Leaked NSA Designs

FinFisher is a German company that makes surveillance software marketed to law-enforcement agencies. The software is designed to siphon off and intercept all kinds of data from a target's computer or cellphone, including Skype calls, emails, and chat conversations.

It made headlines for the first time in 2011, when protesters in Egypt uncovered documents indicating the security services of then-President Hosni Mubarak had purchased its products. Subsequent research has revealed that some repressive regimes around the world have used FinFisher software to spy on dissidents or human rights activists. These episodes have since put Western companies that sell hacking tools to such governments into the spotlight and sparked a debate over the legality of the sales.

In addition to the company's clients, Wikileaks has published actual copies of the software FinFisher sells to governments worldwide, in hopes security researchers can investigate further and build better defenses against these technologies.