"Ransomware has become an increasing problem during the last several quarters and the situation continues to worsen. The number of new, unique samples this quarter is greater than 312,000, slightly less than last quarter but still the second highest figure recorded by the firm," the McAfee Labs Threats Report Third Quarter 2013, said.
Not only do criminals make relatively safe money from this scheme, they often do not remove their malware-leaving the poor victims' systems as dead as before, it said.
One reason for Ransomware's growth is that it is a very efficient means for criminals to earn money because they use various anonymous payment services, it added.
"This method of cash collection is superior to that used by fake AV products, for example, which must process credit card orders for the fake software.
"Another reason is that an underground ecosystem is already in place to help with services such as pay-per-install on computers that are infected by other malware, such as Citadel, and easy-to-use crime packs are available in the underground market," McAfee said.
The US-based cyber security major also reported about 700,000 new Android malware samples, up by 30 per cent, during the third quarter signifying an increase in the number of attacks on the mobile operating system.
Malware, also known as malicious software, threats on mobile phones has also increased, especially Android.
"Despite responsible new security measures by Google, McAfee Labs believes the largest mobile platform will continue to draw the most attention from hackers given it possesses the largest base of potential victims," it said.
Nearly 700,000 new Android malware samples appeared during the third quarter, as attacks on the mobile operating system increased by more than 30 per cent, it added.