According to media reports, the Google Play Store removed the app after learning that it had recently begun delivering a trojan-horse virus.
Recent versions of the app included a new advertising library that contained malicious code that delivered malware to Android devices, according to Russian-based antivirus tech giant Kaspersky, cited by ZDNet.
Kaspersky noted that the "malicious code may show intrusive ads and sign users up for paid subscriptions".
The so-called trojan virus contained within the Camscanner PDF app is configured to connect to the attacker's servers, download additional code and then execute that code on Android devices that have the app installed, according to Kaspersky.
The app is no longer available in the Google Play store. A corresponding iOS version, however, is still available on the online Apple Store.
The Shanghai-based company reportedly relies on ads and in-app purchases to earn revenue from CamScanner. The company specializes in optical character recognition (OCR). Apart from its CamScanner app with OCR text-reading functionality, the firm sells apps that capture text from business cards, ZDNet noted.
Intrusive ads may be pesky, according to Kaspersky, but no consumer wants to pay for subscriptions they never signed up for.