Ads 'biggest mobile malware risk'

Although a small percentage of all malware attacks, mobile malware is growing

Adverts on websites are now the biggest source of malware on mobile phones, according to a study.

Research by security company Blue Coat suggests web adverts have overtaken pornography as the most common way for users to encounter a malware threat.

On one in five occasions when a mobile user comes into contact with malware, it is via an online advert.

Mobile malware is growing, but accounts for just 1% of all malware threats, networking company Cisco says.

Although web adverts have replaced pornography as the most common way for users to encounter malware, attacks from X-rated sites are still the most effective.

Less than 1% of all requested content on a mobile is for pornography, yet it is responsible for 16% of malware attacks.

'Malicious sites'

"While users don't access pornography that frequently, when they do, they are very vulnerable to malware," said the report.

In comparison, Blue Coat say, adverts make up 12% of requested content but are responsible for nearly 20% of attacks.

The adverts are often displayed through "legitimate ad networks" but contain "malicious code" or direct users to "malicious sites".

The report states that the threat of malware from web ads has increased almost three times since it last looked at data relating to the trend in 2012.

Cisco's 2014 Annual Security Report noted that although mobile malware was "not a significant percentage" of web malware encounters "it is still worth noting because mobile malware is clearly an emerging area of exploration for malware developers".

It also found that when mobile malware is intended to compromise a device, it is nearly always targeted at Android devices.

But when mobile malware is not specifically designed to target certain types of devices, then 70% of the attacks were experienced by Android devices and 14% by Apple iPhone users.

Blue Coat recommended that mobile users considered blocking web ads on their devices to prevent them becoming victims of a malware attack.

Ad-blocking apps exist for both Android and Apple devices and browser settings can be adjusted to prevent ad pop-ups.