Aside from avoiding any downloading of apps on an unverified site, perhaps its high time to invest a little more on our systems / mobile device's security (e.g. subscribing to popular security apps) that would minimize our chances of being pawned.
If we can't do it, at least we should regularly update any antivirus apps that we have to keep our defences more active.
I have always had an attitude towards my mobile device in the same way as to my computer, which means that I have always taken care that it has the latest update and that it has some solid AV, with of course great caution for every app I install from Play Store. The problem is that many of today's mobile devices are out of date (too old to get updates) and apps like AV slow them down because of the very low RAM and weak CPU - and that's exactly what hackers are counting on.
That is correct! Most of today's mobile antivirus / security apps are very resource hungry that majority of low-end to mid- range mobile devices owners don't have the required resources as what you've pointed out (e.g. RAM, slow CPU and low storage...) to install good security apps.
Moreover, what is more bothering here is that a significant number of mobile device owners appear to be less security conscious or doesn't have even the elementary skills to enhance their devices security and won't even bother to install security apps - hence creating more easier attack vectors for hackers.