Ransomware is growing fast and could become more difficult to tackle as the criminal ecosystem shifts from a few dominant players to many smaller ones.
Tech security company Bitdefender analysed Windows security threats including ransomware, coin miners, fileless malware, PUAs ('potentially unwanted applications' that can compromise privacy or security), exploits (attacks based on unpatched or previously-unknown vulnerabilities) and banking Trojans.
Bitdefender found that of all these threats, ransomware reports saw the biggest year-on-year increase – 74.2%. Ransomware also ranked first in terms of the total number of reports.
According to the security company, the number of ransomware reports actually dropped during the first half of 2019, largely because the group behind the GandCrab ransomware throttled down their operation.
But since then, ransomware reports climbed again as new ransomware has emerged to fill the void left by GandCrab (it's also possible they have now restarted operations).
While new ransomware such as Sodinokibi (aka REvil or Sodin) have not replaced GandCrab, they are seeing growth.
"The fall of GandCrab, which dominated the ransomware market with a share of over 50 percent, has left a power vacuum that various spinoffs are quickly filling. This fragmentation can only mean the ransomware market will become more powerful and more resilient against combined efforts by law enforcement and the cybersecurity industry to dismantle it," the report said.
Bitdefender said reports of coin miners and fileless malware both declined slightly in the period, although it noted: "With cybercriminals intrinsically motivated by profit – and as a result investing time and effort in building threats that find alternatives ways of providing that – cryptocurrency miners are not likely to go away any time soon."
All this focus on Windows means that malware writers have little time for Macs – or at least those owned by the average computer user. "With Windows remaining a lucrative battlefront, there is little incentive for malware authors to invest time and resources to develop mass-market Mac-centric threats, focusing mostly on advanced and sophisticated threats designed for C-level executives and decision makers," said the Bitdefender report.
But before Apple fans get too smug, that's not to say Macs are not immune to threats: ransomware may be scarce on macOS, but it has been "easily" targeted by cryptojacking operations, attacks using known vulnerabilities, and what Bitdefender calls 'potentially unwanted applications' – software that may be useful but may also compromise privacy or security.
In the first half of 2019, some of the most common threats directed at macOS revolved around coin miners, PUAs and exploits, according to Bitdefender telemetry. While most threats involving coin miners leverage compromised websites that "borrow" computing power to manufacture cryptocurrency, some attacks aim to steal user cookies from cryptocurrency wallets that frequently contain login credentials for various cryptocurrency exchanges.