The apps offered different functionality: computer and battery optimisation tutorials, Internet search, Web browsing, and downloading. They were created by three developers: DigiDream, 1clean, and Findoo.
The samples of these apps found by the Symantec team ran on Windows 10, including Windows 10 S mode.
All the apps were published between April and December 2018 with most making an appearance towards the year-end.
"Even though the apps were on the app store for a relatively short period of time, a significant number of users may have downloaded them," Symantec said.
"Although we can’t get exact download or installation counts, we can see that there were almost 1900 ratings posted for these apps.
"However, app ratings can be fraudulently inflated, so it is difficult to know how many users really downloaded these apps."