Trojan horses are the most dangerous online threats of 2017

The Trojan horse was the world's most dangerous online threat during the first eight months of 2017, according to stats from antivirus software maker Avira.

Trojan horses alone account for 60% of online threats recorded by Avira, with more than 788 million detections during the first eight months of 2017. Trojan horses are malicious programs that are disguised as useful or helpful programs to trick users into downloading them. Perhaps the best-known kind, due to recent media attention, is ransomware. This software encrypts user data and holds it hostage, demanding a ransom to be paid for its release.

The second most common threat comes from exploit kits, with more than 222 million cases detected by Avira. These programs exploit security weaknesses -- such as security flaws in software or out of date programs -- to infiltrate and infect a device. They are mainly spread by infected websites or by email.

Next in line are PUA -- Potentially Unwanted Applications -- with 173 million detections. These programs are often unknowingly downloaded by users alongside legitimate apps and are dangerous to different degrees. They are often maliciously integrated into download and installation processes.

Finally, with almost 131 million detections, phishing scams use fake and fraudulent websites (mimicking an institution or online retailer) to trick users into handing over personal data, such as addresses and bank details. Most of the time, links to these fake sites are sent to users by email or text message. The Avira stats cover the period from January to August 2017.