The number of security threats on mobile networks has increased in the first half of 2015, a study by Alcatel-Lucent revealed Wednesday.

The study entitled Motive Security Labs H1 2015 Malware Report found that 80 percent of malware infections detected on mobile networks have been traced to Windows-based computers and laptops.

This finding represents a significant change from 2013 and 2014 when the source of mobile network infections were roughly split 50:50 between Android and Windows supported devices, Alcatel-Lucent said.

“The modern smartphone also presents the perfect platform for corporate and personal espionage, information theft, denial of service attacks on businesses and governments, and banking and advertising scams,” said Patrick Tan, General Manager of Network Intelligence at Alcatel-Lucent.

The research also found a significant increase in the number of ‘spyphone’ apps being detected on both Android and iOS mobile devices.

Alcatel-Lucent has found that PCs and laptops are the favorite targets of hardcore professional cybercriminals who have invested heavily in the Windows malware ecosystem.

The Motive report also found that cybercriminals are quickly taking advantage of unique opportunities in the mobile ecosystem to spread spyware.