Have you ever bought a used storage medium at an online auction or, worse, sold your SD card or flash drive? If so, I hope you have taken care of the proper deletion of your data. However, as you did, it belongs to the minority. An experiment conducted by scientists from the Cyber Security Center of the University of Hertfordshire shows that without any difficulty you can recover data belonging to previous owners of used SD cards.
People, who care about privacy, know that you should not sell old storage media and hard drive computers. The exceptions are only those data carriers that have been previously erased and prepared for sale. Although companies specializing in data recovery have their own ways of recovering overwritten files, but using home-made methods, we can ensure a sufficient level of security. Unfortunately, most people do not realize that simply deleting files or quickly formatting an SD card is not enough. After such treatments you can easily recover “deleted” data.
Cybersecurity researchers have studied 100 used SD cards
Memory cards are currently widely used, and people are eager to exchange them for larger models. That’s why you can find a lot of used SD cards on online auctions. Researchers from the Cyber Security Center of the University of Hertfordshire bought 100 used SD cards at online auctions and checked their content. Only 25 of them were cleaned before sale by means of a dedicated program. This means that all memory has been overwritten by zeros (or other characters). 29 cards have been formatted, but scientists have recovered the data they have saved without any effort. Two more cards had deleted files, but also here you could easily restore them. For 4 cards, researchers could not determine how to delete data. However, the most cards purchased, as many as 36, contained files that were not removed in any way.
What did the files found on the purchased SD cards contain? Most of them were photos and multimedia files (video and audio recordings). The researchers also found many private documents (including several CVs) and business files. However, on several cards there were sexual materials. Most of the purchased SD cards were previously used in smartphones and cameras. Therefore, apart from many selfies, the researchers acquired telephone numbers (including vcard files), e-mail addresses, addresses and names of previous owners of SD card and their friends. In addition, one card even had a credit card number for one of the British students.
Therefore, remember. Before you sell your storage medium or an unnecessary computer, make sure you delete the data correctly. Only one of the free programs (e.g. Hardwipe or Eraser) can be used for SD cards, pendrives and portable hard drives. In contrast, in the case of laptops, I recommend the Ultimate Boot CD toolkit, where you will find several programs dedicated to delete data.