Gamma International UK Ltd. touts its ability to send a "fake iTunes update" that can infect computers with surveillance software, according to one of the company's marketing videos.

The Wall Street Journal unveiled on Saturday the "Surveillance Catalog" – an online database containing highlights from surveillance industry marketing documents. The documents show dozens of companies making and selling everything from "massive intercept" gear that can gather all Internet communications in a country to "hacking" tools that allow...