I am going to China. If I take my Samsung smart phone and get a local SIM card for calling only (no text, no data), turn off wifi, Bluetooth, and NFC, should my phone be safe as far as the stored data is concerned?

  • 1
    Is it a business trip? Do you need to securely communicate with somebody who might be already under surveillance? Could the stored data get you in trouble with competitors or local authorities?
    – A. Darwin
    Sep 30 '16 at 13:00
  • 1
    Hello and welcome to Information Security! I think you need to be a bit more precise. What is it that you are worried about?
    – Anders
    Sep 30 '16 at 13:03
  • The stored data is basically social media accounts and credit cards, so I don't want my data to be hacked (I don't care if somebody listens in on my conversations). I assume I will be under surveillance, even though this is a personal trip. All I need is to have a local number in case I have to reach the tour guide or our friends' hotel room. A burner phone is another option.
    – Jeff
    Sep 30 '16 at 13:27
  • 2
    Backup the phone, reset the phone, go to China, come home, reset it again and finally restore from backup?
    – R15
    Sep 30 '16 at 13:55
  • Why take your phone? Get a burner over there. Without wifi or data, what benefit do you gain by taking your smartphone?
    – schroeder
    Oct 1 '16 at 7:38

If you don't care about your calls being monitored, you could backup the stored data and reset the phone before the departure, reset it again and restore from the backup after coming back home (as R15 suggests).

However, you need to keep in mind that Chinese intelligence agencies occasionally enter hotel rooms and perform low-level copies of your laptop and phone (some kind of "forensic acquisition", like those made by conventional law enforcement agencies). Factory reset may not be enough and a skilled attacker may be able to recover the erased files. You can mitigate, but not completely remove, this risk

a) either by moving your sensitive files to a removable card (which you cannot bring to China), overwriting the memory with random notes, irrelevant pictures, and so on, encrypting the phone, and factory reset it,

b) or by simply buying a burner phone.

You should also be careful about charging your phone.

It's possible to replace your phone's charging equipment with a malicious doppelganger while you're gone, or even while you're asleep.

If you spend enough time in hotels, you may run even into hotel employees who actually enter your hotel while you're asleep. Even if you've bolted the doors and locked them.


Note that this risk could be mitigated by buying a cheap burner (dumb)phone. "Dumbphone" batteries usually last for a rather long time, which means that you may be able to stay in China for, say, a week without having to charge your phone.

  • 1
    I'd give this multiple upvotes if I could. As a matter of policy, we forbid employees from bringing their day-to-day corporate equipment to China/Russia, and especially trying to connect to the corporate network from either location. Instead we supply loaner laptops and forensically examine them for malware upon return. For personal items, I doubt you'd be targeted, but if you have any professional or government significance just leave it all at home.
    – Ivan
    Sep 30 '16 at 16:35

It depends on your risk profile. You can assume Chinese intelligence services will be just as liberal as their western counterparts to infect hardware if not more so.

You can blindly assume cell towers are controlled or spoofed in China. If you are of special interest to state actors chances are good an exploit will reach you over those cell towers.

The only way to proplerly guard stored data is to encrypt it well. But then you still need to guard the device to protect the keys.

But hey, seeing as phones are generally manufactured in China any damage will probably already be done.

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