Researchers have noticed one of the first examples of Android 'drive-by' malware from an ordinary website, a dangerous type of automatic attack more commonly used to infect Windows PCs.
Any Android browser visiting an affected page (the attack ignores PC browsers) will automatically start downloading the malware without the user being aware that this has happened,
This isn't quite a PC drive-by attack because the user still needs to install the app, at which point it relies on the user having ticked the 'Unknown Sources' box (in most cases this box would be unticked) that allows non-market apps to be installed.
The rough equivalent of this layer on a Vista or Windows 7 PC would be the User Access Control (UAC) which is usually circumvented using social engineering or by misrepresenting the nature of the application.
NotCompatible eschews such tricks beyond simply claiming to be a security update. It's not sophisticated but it might fool some users, some of the time.
The purpose of the infection is a bit of a mystery.
"This specific sample, while relatively well constructed, does not appear to go to great lengths to hide its intended purpose: it can be used to access private networks," said Lookout's blog.
"This feature in itself could be significant for system IT administrators: a device infected with NotCompatible could potentially be used to gain access to normally protected information or systems, such as those maintained by enterprise or government."
The affected sites appeared to have low volumes of traffic but the company believed the exploit iFrame was being served on other sites it had yet to identify, it said.
The warning is stark; mobile malware creators are experimenting with what is possible for this class of malware and have found a way to get mobile malware on to devices without them having to visit third-party app sites as has been the case up to now.