Access to a smartphone can tell you everything you need to know about a person.

But with those mischievous advertising firms now sending information to third-party servers, is the line between aggressive advertising and malware even blurrier?

While such revelations are not exactly new, a recent study on some 130,000 popular free Android apps revealed that aggressive advertisers breach user privacy by uploading phone numbers to third-party entities.

Nearly 13% of analysed apps were found to collect and broadcast users’ phone numbers without explicit notification, according to security company Bitdefender.

Location data and personal email addresses were also accessed and distributed to third parties by 12% and 8% of analysed apps respectively.

“The thin line between aggressive advertisers and malware is getting blurrier,” says Catalin Cosoi, chief security strategist, Bitdefender.

“While malware may steal passwords and other credentials, aggressive advertisers may collect everything else.

"Although violating user privacy raises serious concerns, the risk of having collected data used for malicious purposes is greater than most people imagine.”

While some apps may legitimately require access to such data, others access it without the app explicitly needing it to perform adequately.

Apps that access browsing history sum up to 6%, while some apps even require access to photos.

Although some analysed apps have been updated to meet proper user privacy guidelines, previous versions of Texas Poker, by KamaGames, and Paradise Island, by Game Insight International, uploaded user phone number to third parties.

Android users are advised to exercise extreme caution when installing apps and to always check for what permissions they require.

Installing a mobile security solution that can detect virulent adware is also recommended, as data privacy should be a top priority.

Is the line between aggressive advertisers and malware getting blurrier? Tell us your thoughts below