Ransomware attacks on Android system rose four-fold 12 months: Kaspersky Lab

The number of ransomware attacks targeting Google's Android operating system has risen four-fold in the past 12 months.

Ransomware attacks have been most commonly seen on desktop devices, with criminals using specific strains of malware to lock devices and deny access to files and data.

The hackers unlock the devices only on the payment of ransom usually in bitcoin.

Hackers now seem to be turning to mobile ransomware, after data from Kaspersky Lab revealed that it stopped 136,532 ransomware attacks between March 2015 and March 2016 based on metrics from its own tools on smartphones.

This comes as a near fourfold increase on the 35,413 attacks in the previous 12 months.

The rise also saw mobile ransomware take up an increasing share of all malware attacks stopped by Kaspersky, from 2.04 per cent in 2014-2015 to 4.63 per cent in 2015-2016.

''The growth curve may be less than that seen for PC ransomware, but it is still significant enough to confirm a worrying trend,'' the firm said.

Kaspersky's data further showed that UK citizens were among the most likely to be targeted by mobile ransomware. Some 16 per cent of all mobile ransomware attacks struck users in the country.

However, those in Germany ran the highest risk at 22.9 per cent, followed by Canada at 19.61 per cent.

Meanwhile, Kaspersky also detected malware that had been targeting Facebook users and their accounts.

The security firm reported having detected around 10,000 Facebook users accounts that had been affected.

These ranged from countries such as Brazil, Poland, Peru, Colombia, Mexico, Ecuador, Greece, Portugal, Tunisia, Venezuela, Germany, and Israel.

The malware that infected the accounts managed to disguise itself a message from a user's Facebook friend. The message mentioned the ''friend'' had mentioned them in a comment.