What are the circumstances in which it's not foolhardy to have access to your primary email address through your smartphone?

Question

Most web sites I use allow a password reset through email; a few require two-factor authentication with a phone call or SMS. It would perhaps only be banking or major commerce sites that would require some additional authentication factor.

So having a “Gmail” app on my smart phone (or linking my primary Gmail address to my smart phone) seems incredibly foolish to me. Outside of having a very complex screenlock password, I'm giving anyone who steals my phone access to all of my accounts. (So, in my case, my Android phone is linked to a dummy Google account, which I have only so that the phone will work.)

Is there wise way to have email access through one's phone? Or does everyone just accept that risk?

Answer 1

Unfortunately, no one can answer this question for you. You need to formalize your threat model if you want to be able to understand the risks. Start with the understanding that unlimited access to your phone provides access to your Gmail password. You then have to consider who your adversaries are and how likely they are to gain such access to your phone, for example:

• Thief - The average thief is likely to steal your phone and just pawn it off if they can't open it easily. This kind of attacker is unlikely to be after your Gmail password specifically, but would still utilize it for their own purposes if they were to obtain it. Protecting against them is as simple as using a strong form of authentication for your phone. Note that a thief could simply take your phone while you have it out and unlocked. It is not uncommon for someone to ask for the time and, when you pull out your phone to check (if you have no watch), they snatch it and run. These thieves are more likely to be able to access your Gmail.

• Stalker - A stalker or another unsophisticated attacker who wants access to your Gmail or other personal information may target you specifically. However, they will not be able to easily unlock the phone unless the password is particularly weak (something they might guess).

• Nation state - An advanced adversary who wants access to your Gmail would be able to compromise your phone as long as it is powered on, regardless of whether or not it is locked. However, you must realize that this particular adversary might also be able to directly access your Gmail (e.g. via subpoenas). While there are certainly attackers in this class that need your phone to access credentials, you have to decide whether or not they are yours.

If you do not have a particularly sophisticated attacker out to get you specifically, and as long as the content on your email is not so valuable that people will dedicate significant resources to obtain access, then you really only need to make sure that your authentication method is secure (e.g. a strong password), and that you keep your phone locked whenever you are not actively using it. Make sure you keep the software up to date so there are no known screenlock bypasses.

Answer 2

If you want to prevent an attacker from using your main account (and therefore having access to all your accounts if they rely on the main account for password recovering), then all you have to do is probably two things:

1. Block your phone number. It depends on your provider, but when your SIM gets stolen they should be able to block the number pretty quickly.
2. Go to Google and try to disconnect your account from all devices, and then change your password.

As for the "lock and erase" feature, I'm not sure how much it can be relied on. I read that localization (GPS) has to be turned on for it to work. Also, an internet connection is needed of course. So if the thief just turns off the data connection, or pulls out the SIM card, or maybe just turns off the GPS, etc., you might not be able to "lock and erase" the device. Or you might not be able to do it quickly enough, anyway.

So, if you want to prevent an attacker from also reading your email, accessing your documents, etc. (all things that are saved on your phone), plus also protecting from attackers that steal your phone from your hands (so it's unlocked), then I'm afraid there's no way to do it, unless you accept to mitigate the risk some ways, for example:

• Only associate your device with a Google account that you only use for the phone and nothing else (a kind of "dummy" account)
• Don't send and receive any email from other accounts
• If you want to read the mail from some accounts, set up a forward copy to be sent to your "dummy" Google account of your device, and whenever you read an email you must remember to delete it
• ...

Basically you will need to accept that you can't use such a phone easily for work, unless maybe you are ok with only reading the emails and then immediately delete them. But you won't be able to do many more things, as it will basically be like running around in public with your office in your hands, waiting for a thief to steal it.