There is an update app appearing on iPhones asking you to update Adobe Reader for free, and you are then asked to input your password. It looks genuine but isn't. I queried it because I didn't load Adobe Reader on to my phone. It's malware that attempts to access your card details. If you see it, the advice I have read is to delete Adobe Reader immediately. You can always get it again off the App Store. Adobe say they NEVER send emails or invitations to update what's free by just going to their website to download. I didn't know that - been updating for years, but fortunately haven't suffered as a result. Apparently, we shouldn't open these emails, eiher - just delete.
I've got another 'keen'... Ouch!