It seems that the widely popular Avast! Mobile Security app is labeling apps like Gmail, PayPal, Google Currents, LinkedIn, Redbox, Amazon and WhatsApp as malware. This is what you would call a false positive.
If you aren’t familiar as to what a false positive is, let’s say you theoretically went in for a cancer test. The test would come back and test you positive for cancer when actually you don’t have cancer. That would be a false positive. On the flipside, there are false negatives where you would be tested for cancer with the test coming back and saying you don’t have cancer, but in reality you do.
The good news is that, according to the Avast! support forums, an update is being rolled out to fix the problem. Support forum moderator Filip Havlicek writes:
it seems that this false positive detection somehow got through our systems to everyone. I’m sorry for that. Don’t worry though, there should be a virus definitions update soon that will remove this detection. I’m going to reroute all topics to this one and lock them so everyone knows what’s happening. I’ll post here when the update is out so everyone can do a manual update of their definitions to fix this (or you can, of course, wait for the automatic update to happen, but manual will most probably be faster in this case).
Some users in the forums are already reporting that they’re getting the update. So, if you run Avast! Mobile Security on your smartphone, you may want to check for an update as soon as possible. If the update does not solve the problem, running an app scan should clear the definitions and everything should be normal again.