A security researcher discovered a vulnerability in the Android MMS system which could be exploited to control Android phones without the user doing anything. It was reported to Google in April and a patch was release.
Unfortunately, as is the case with most manufacturers, the Android system rarely gets more than one or two upgrades.
The vulnerability affects Androids 2.2 to 5.1.1 which is the majority of smartphones currently in use.
To reduce the risk of being exploited you should disable MMS auto-retrieval in you SMS app, Hangouts app, and any other apps that deal with your SMS & MMS. To do this go into the settings of each app and disable MMS auto-retrieval. See the images below as a demonstration as well as the link at the end of the post.
For more on the topic and to stay updated follow the topic on Quora and these threads & articles:
Stagefright Android MMS Vulnerability (July 2015): What is Stagefright Android MMS vulnerability?
How do I protect my Android phone from the Stagefright vulnerability? FAQ
How To: Protect your Android device from the MMS-hack (Stagefright exploit)
Latest news about Stagefright
This is a list of my top Android apps:
- SwiftKey keyboard: replaces the default keyboard and adds the “flow” feature $$
- Sunrise calendar + DigiCal + Google Calendar*
- Twilight: adapts the screen to the time of the day by making it red accordingly.
- Easy Battery Saver
- Timesheet: for time tracking
- Wunderlist: for task management f/$$
- Sleep as Android (unlocked): for sleep tracking and as an alarm clock $$
- GnuCash: for bookkeeping
- Evernote: for notetaking f/$$
- Google Drive + Docs + Sheets: for writing on the go
- Pocket: for reading web articles offline free of ads and distractions
- gReader Pro: for reading feeds (integrates with Feedly) f/$$
- Moon+ Reader Pro: for reading ebooks f/$$
- Plume: for tweeting
- WolframAlpha: for instant expert knowledge and computation $$
- CamScanner: for scanning documents by taking images f/$$
- Smart Audiobook Player f/$$
- Link Bubble: to open links without leaving the current app. Very handy.
- f: free
- $$: paid
- not indicated: free
* DigiCal is great for its Cut/Copy and Paste feature while Sunrise calendar has a great user interface and offers (for free counter to DigiCal) the feature to add other calendars to integrate Evernote (for reminders), Facebook (for birthdays & events) and other services.