Imagine you leave your smartphone in a hotel room for half an hour.

Screenlock is on. Latest security updates are installed.

How could somebody steal your data from the device given enough expertise is given? (being realistic though)


  • files
  • passwords saved in browser
  • clipboard memory
  • address book and call data
  • biometric data i.e. fingerprint data

This scenario does not consider stealing data stored on the SIM card (assuming the screen lock is not saved in an unencrypted plain text string there irony)

  • 1
    I think this is too broad. It's possible depending on who the hacker is. Usually it takes a good bit of expertise to do so, but it is certainly possible. As for fingerprints... well you leave that on the surface of the phone.
    – forest
    Commented Dec 5, 2018 at 11:16

4 Answers 4


This depends on the implementation and configuration of your smart phone, but smart phones can be pretty secure. In the FBI–Apple encryption dispute, the FBI took more than a month and spend more than one million dollars to access the data on an iPhone.

  • The FBI is far from the most technically-capable organization out there.
    – forest
    Commented Dec 6, 2018 at 2:05

without specifying what device and OS there is no way to say with certainty what is possible.

However in general be aware that the following is possible for a state-level attacker with physical access to your device. (this list is not exhaustive)

  • Attach a "Listener" device to it, this could be inside the device clipped to datelines / IC.
  • Install software through the exposed USB port. Any software!
  • Replace your device with a duplicated device that has all the listening stuff in it.
  • Extract a Memory dump from the device to analyze later.

The SIM card is actually one of the parts that are 'safe' from manipulating if a password besides 0000 is set. It is a tamper resistant smart card that actually stores the keys needed to encrypt your phone communication (excluding WIFI/Bluetooth and Wired) It is far easier to request a duplicate SIM from the issuer than to extract any (meaningful) data from the SIM card itself.


Many people claim that certain nation states bug foreigners' hotel rooms

Here is how I would compromise that phone.

  1. Install covert CCTV in the rooms. Foreigners are sometimes limited to specific hotels and CCTV is cheap
  2. Watch, watch, watch. Wait, wait, wait
  3. Once you have seen the user put in their code you can take the phone. Or take it at the airport. "customs check my friend"

To force someone to use the PIN rather than biometrics, replace the phone with an exact copy so the victim is forced to try everything they can to get in. Admittedly getting an exact copy is going to be a task.

  • This scenario is outside the stated threats.
    – schroeder
    Commented Aug 30, 2019 at 8:23

I was only reading about this a few days ago, and it would appear that if your smartphone is android based, and has a qualcomm chipset then several vulnerabilities allow remote compromise over the air.

The vulnerabilities in question are:

CVE-2019-10539 (Compromising WLAN) — The first flaw is a buffer overflow issue that resides in the Qualcomm WLAN firmware due to lack of length check when parsing the extended cap IE header length.

CVE-2019-10540 (WLAN into Modem issue) — The second issue is also a buffer-overflow flaw that also resides in the Qualcomm WLAN firmware and affects its neighborhood area network (NAN) function due to lack of check of count value received in NAN availability attribute.

CVE-2019-10538 (Modem into Linux Kernel issue) — The third issue lies in Qualcomm's Linux kernel driver for Android that can be exploited by subsequently sending malicious inputs from the Wi-Fi chipset to overwrite parts of Linux kernel running the device's main Android operating system.

Once compromised, the kernel gives attackers full system access, including the ability to install rootkits, extract sensitive information, and perform other malicious actions, all while evading detection.

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