Is there a chance USB files once opened by TV, PC etc. have any footprint, backup or residue files left on the hosting device it worked on?

Question

Let me first thank you all for the great info. you are providing. My question is; Do files stored on USB once opened and viewed by TV, PC etc. have any footprint, backup or residue files left on the hosting device? If yes, are the files recoverable from the TV or PC it was previewed on alone without using or accessing the USB source? I am asking because, I am specifically worried that If I use my TV or even my PC to view or watch my personal and private videos or pictures which are stored in my USB, somebody else through the internet could have access to it and recover it once my personal TV or PC is connected to the internet even that the files not saved or copied to the TV or the PC? Is there any chance for such a scenario to happen? I might be overthinking this, anyhow I hope I am not wasting your time for such a question.

best regards,

Answer 1

"Opening" a file is not magical. This means: running some local application which will read the file contents, and do something sensible with them.

A USB flash drive is a storage device; its purpose is to store bytes and give them back when asked to. When you "open", say, a video file on a PC, the following happens:

• The operating system on the PC tries to infer the file type, based on clues such as the end of the file name (the so-called "extension"): if the file name ends with .mp4, then the OS will think that "this is a video file".
• The OS launches its video file reading application (e.g. Windows Media Player, or VideoLAN, or whatever was registered in the OS as "the default video file reading application"), giving it as parameter the file name.
• The application will then read the file and process it, e.g. playing the video before your amazed eyes.

Now a video player will not normally save a copy of video data in other files; however, it may save some meta information. For instance, when I "open" a video file on my PC (which runs Linux), the default media player begins playing it. If I close the player, then "open" the same file again, the software asks whether I want to "resume playback" at the point I left previously. This can happen only if the player remembers that I played that file before, and where I stopped; this must be written somewhere, and, in particular, it is not written in the file itself, or (apparently) in the same directory. Basically, this means that some information (including, probably, the file name) is stored in a directory in the local hard disk. This answers your question:

• Yes, it may happen that the names of files that you play may be stored somewhere on the playing device. It routinely happens for millions of PC.
• No, usually, the file contents won't be saved on the playing device, because it is way too large to make this strategy viable.
• However, if the video file was downloaded from "the Internet" at some point (e.g. Youtube), what the device saves might be enough to reliably identify that video later on (assuming that the place from which it was downloaded still has it).

Answer 2

That is perfectly possible. Just a few weeks ago we learnt about some television brands that send the file names to their servers (we don't know with which purpose). You can learn a bit more in this link: http://www.tomsguide.com/us/lg-smarttv-spying,news-17874.html

Nevertheless, I haven't seen the televisions to send the actual files, but you never knows, that's completely possible, once the television sends the file names it can also send a screencap, that wouldn't be very hard... But I don't know if the brands will dare to do such a thing...

Also, now the televisions are connected to the internet we will see with the time, televisions infected with virus and this kind of behaviour is completely possible.

The best way to be sure is never to connect the television to the internet, but if you really need to connect it, you may spy what the television is sending to the internet by analyzing its traffic or you can whitelist only the domains you want the tv to access.

Answer 3

No, there is no such thing. Unless your device(TV, PC or USB drive) is infected with something malicious. When your file is opened on the hosting device, the only place for which it is copied to is the RAM memory of the hosting device. Once the process responsible for rendering the file terminates (either because you removed the USB device or closed the video / image) previously allocated RAM memory is released so other processes can use it, and so the information pertaining to your file is lost.