More than a third of computers users were subject to a web attack during this year, according to data from the security company Kaspersky Lab.

Feedback from the firm’s products showed that 6.2 billion attacks on computers and mobiles were detected and blocked during 2014, a billion more than the previous year, with notable activity on the mobile side.

Roman Unuchek, senior mobile malware analyst at Kaspersky, said: "2011 was the year of mobile malware formation, especially on Android-based devices; 2012 was when they developed and 2013 was when they reached maturity.

"In 2014 mobile malware focused on financial issues: the number of mobile banking Trojans was nine times greater than in the previous year and developing in this area is continuing at an alarming rate."

Financial malware has also been prevalent this year, with Zeus remaining the most popular banking trojan and, banking malware accounting for three-quarters of attacks with a financial focus.

The second most popular banking threat was that of Bitcoin wallet theft, which accounted for 14% of financial attacks, while the third most popular involved Bitcoin mining software, which solves algorithms to generate digital cash.

Maria Garnaeva, security expert at Kaspersky, said: "One of the most effective ways to deliver malware to user computers is to exploit vulnerabilities in Oracle Java and in browsers such as Explorer, Mozilla Firefox, etc.

"In addition, cybercriminals continue to use exploits for Adobe Reader vulnerabilities. These infection techniques remain popular simply because social engineering techniques are still effective."