I use Linux for half a decade now, so I am not used to dealing with viruses anymore. To my surprise, I saw some discussion about antiviruses in Android. I haven't installed any yet, but this bugs me: are they really necessary? Are there (or were) any known viruses in the market? Doesn't Google runs an antivirus before allowing an app to the market?
I haven't had no problem in one year of Android, but my cellphone has a lot of important information, and I wouldn't like to be surprised with some virus cleaning my phone, or making international calls while I sleep, or whatsoever. Should I install an antivirus?
You shouldn't need to worry about running an anti-virus on your phone. I would recommend running one on your PC though and having it set to scan peripheral devices. When you plug in your phone and it gets mounted as a mass storage device the desktop's antivirus will scan the phone for viruses' signatures and you will be doing the minimum to ensure your security.
It is an illusion to believe that just because you are running *nix or OSX you won't benefit from the security afforded by AV software; that said you dont need to spend anything to get a good, lean program especially in Linux.
There have been a few reports of Trojans that basically pretend to do something, but they are actually texting short codes charing you money or stealing data or something. However, I'm not sure how these 'anti virus' programs could actually counter that as they don't have anyway to monitor what these other apps are actually doing.
All you really need to do is take a close look at the permissions requested when you install an app, and ask yourself 'should this app need full internet access and contacts access and location?'
Always read the required permissions before installing any application, and ensure that this application needs these permissions for its function and not just asks to do some crap on your phone. Do not allow any application to take permission to tamper with your phone information.
Installing an anti-virus app will slow down your phone, so better scan for viruses from your PC.
Antivirus isn't as necessary as it is on Windows but it isn't a bad idea to have it. Google does check apps that are submitted to the Play Store as far as I am aware. However, there have been a few incidents of malicious apps on the Play Store and people downloading these. The bigger issue is apps from outside the Play Store, especially if your device is rooted. It's probably sensible to have antivirus software installed, especially since they are so effective, according to the AV-Test Android results here, where some programs get close to 100% detection rates. This website also includes 'Usability', which includes whether the antivirus slows down the device during normal usage.
In Android Market was only few viruses so the possibility of catching an virus is rare occurrence. The problem is when you download the apps from internet. I highly do not recommend it.
What about AV for Android phones?
I am always laughing when people insist that AV for Android device is must have.
Why it is not necessary? Consider what the names like kernel, root etc come from. Android is based on Linux and I have never heard about strong viruses for Unix like operating systems. Yes, there is possibility to create virus, yes it might work but only if you give the app permissions. That is why I think that AV for Android is just a scam.
So to sum up as long as you download apps from Google market feel comfortable and just forget about viruses.