Kaspersky discovered that the app - which was installed more than 100 million times - contained an advertising library with a malicious dropper component.
The component was detected as "Trojan-Dropper.AndroidOS.Necro.n" and was designed to download and launch a payload from malicious servers.
CamScanner was a popular app among Android users which allowed them to scan documents with their smartphone camera and save the content to a PDF document.
The app had 1.8 million reviews, most of which were positive. However, a recent influx of negative reviews pointed to problems with the app's user experience which prompted Kaspersky to investigate the software.