Originally Posted by androidnewbie5
A lot of apps do not really need web access and work fine without such access. With many android apps, especially games, browsers, and the like having spyware elements that phone home, how effective is using a firewall to protect one's data? I ask because I am not familiar with the inner workings of android and wonder if apps can bypass firewalls in android. I use Avast Mobile Security which includes a firewall but wonder if - in android - data goes out anyway. Does it? How secure or insecure should I feel? Thanks.
Be afraid, be very afraid ... it's healthy.
Since data transfers occur using the TCP/IP protocol (Dep't of Rendundancy Dept.), a firewall inspects each and every packet to see if it matches the filtering rules. I'm not familiar with your Avast product, but advanced firewalls like netfilter can be customized to any degree desired by a knowledgeable user.
Let's say your "Married Birds" app needs to store your settings, score and gaming partners in the "cloud", so you grant your app such an "outbound" firewall rule. If the permissions on such a game allow it to collect location, contacts info or anything else, then those also are allowed to be transmitted outbound through the firewall.
There are also "inbound" rules to be considered ... will Google be allowed to "push" updates? Will your web-based cerberusapp.com be allowed to communicate with the phone's cerberus app after the phone gets stolen or misplaced?
Does the firewall app make pre-programmed assumptions about native apps firewall rules?
Such apps as Avast, McAfee et.al. presume little if any knowledge on the part of the user and might present popup dialogs any time such inbound/outbound decisions need to be made. Answering "Allow" may not necessarily function as one expects though, and may not necessarily protect your sensitive data.
So .... be afraid.