Many of those who seek a reduction in the rapidly ballooning costs of smartphones head to the second-hand market. However, there are some significant risks involved in both buying and selling used phones.

It is a common misconception that deleting everything and performing a factory reset can eliminate anything considered dangerous from a device. Personal and enterprise information can remain, as can trojan viruses or malware.

The second-hand market becomes flooded with inventory after big releases from the larger smartphone suppliers, both iPhone and Android. Sellers and buyers are both eager to offload old devices and find a great deal on last year’s models.

Those intending to purchase a second-hand smartphone should be especially wary of devices posted for sale after a new product comes out. Why? Well, because sellers seek to get rid of their old things as soon as possible and they may not take proper precautions before transferring the smartphone to the new owner.

Phones “wiped clean” and listed for resale could have myriad of personal information retrieved with the proper tools and skills.

This is seemingly bad news for the seller, as a savvy buyer could retrieve their pictures, messages, and other private data. However, while these things can be recovered after what many consider a thorough cleaning, viruses and malware are likely to pass through.

Security Steps You Should Take After Buying a Second-Hand Phone

There are some steps to take when purchasing a used device. Following them could help ensure a reasonable level of security before you start using your “new” smartphone.

  1. Stick with major brands that support iOS and Android. They offer more controls and functions that can help provide security and a “clean slate.”
  2. Do a full factory wipe and reset the smartphone. This will validate the operating system and alert you to a rooted or jailbroken device.
  3. Remove any SD or SIM cards. The seller should have already done this, but if they haven’t, starting fresh here is a must.
  4. Engage device encryption. Apple devices typically default to the appropriate encryption settings while Androids are not. Manually turn encryption on if it isn’t already.
  5. Install new firmware, if possible. This step is vital to removing root-level malware.

Advanced Ideas to Secure a Second-Hand Phone

There are further, more advanced precautions to take if you are genuinely concerned with the security of your private information. Contacting the manufacturer with the electronic serial number can provide you with the history of the device and if it has ever been reported as stolen.

It is important to note that when buying a second-hand smartphone, it is virtually impossible to be confident that there is no malicious content on the device. Even after deleting all apps and flushing out rooted malware by reinstalling the firmware, there could still be an advanced malware or virus present.

Consider downloading and using a VPN app on your smartphone. This encrypts any data being sent to and from your device when it is on. This could prevent any intentional hacking of your smartphone.

Security Steps You Should Take Before Selling a Second-Hand Phone

Just as there are inherent dangers to purchasing a used phone, sellers should be cautious, as well. Take the following steps to help avoid accidentally giving away personal information:

  1. Do a full factory reset. This can expedite the process of removing apps and documents.
  2. Remove all apps and associated data. It is imperative that all personal data connected to any applications on the device is removed along with the app.
  3. Remove SD and SIM cards.
  4. Verify the removal of all logs, texts, etc. Take the time to ensure there is no trace of personal information remaining on the phone after the previous steps are complete.
  5. Review cloud syncing. The last thing you want is for sync to process and replace all your personal information and pictures onto the phone you just wiped clean. Disable the device from any clouds it may have been connected to.


The newest Samsung smartphone costs almost $2000. It is not surprising that many people turn to secondary markets for more affordable options. While this behavior is not unreasonable, it does come with some associated risks.

Take the time to ensure your gently used device is as secure as possible. Install a VPN and a good anti-virus app to protect against any vulnerabilities that may still be lurking on your second-hand smartphone.

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