In parallel with F-Secure's report, fellow security vendor Avast says this summer has seen the million pieces of mobile malware milestone crossed.
Back at F-Secure, during the second quarter of the year, the firm says that 295 new threat families and variants were discovered – 294 on Android and one on Apple iOS. This is up on the first quarter, when 277 threats were logged, 275 of them targeting the Android portable operating system.
The top Android threats in the second quarter were Trojans that either send text messages to premium numbers, or exfiltrate data from a device for remote forwarding.
F-Secure says that the most notable piece of Android malware was the Slocker code, which appeared in June and was/is the first TOR-encrypted ransomware.
Unlike the earlier Koler malware, says the report, the Trojan:Android/Slocker malware actually encrypts image, document and video files on the device.
"Like Koler, it also disables the back button to interfere with the user's control of the device. Slocker variants can communicate with their controlling server either via the Tor anonymising network or SMS messages," says the report.
Over at Avast, meanwhile, Ondrej Vlcek, the firm's chief operating officer, says his research shows that mobile malware is growing exponentially - and is now ten times up on 100,000 samples seen in its database back in 2011.
Despite this, he says, the security threat posed by mobile malware is still relatively young, with most code displaying a pretty simple structure, even if it is designed to effectively steal people's money.
"Newer mobile malware is, however, adapting and evolving, slowly embracing more deceitful and complex tactics to target users," he says in his analysis of the mobile malware landscape, adding that the focus of mobile malware has always been on monetisation, meaning that even early mobile malware posed real-life threats to its victims, stealing money from them.
On top of this, he explained, even though malware targeting smartphones and tablets is still young, it is developing much faster than PC malware did in its initial years.
Against this backdrop, Vlcek predicts that, with the emergence of new technologies, malware authors will find new ways of taking advantage of them.
For example, he says, as the use of new payment methods like Near Field Payment increases, he expect hackers will change the way they go after money.