TUE
11:25 20
2017
10-24

Memory Stick Capacity Scam

Feeling fed up with the dross that fills the UK's TV channels these days, I've been spending my evenings entertaining myself with episodes of South Korea's excellent 'Running Man' series from SBS. Sharing the love, I've got @kev_blog and @BootBlock watching it as well, and in order to move a few files around I found myself in need of a larger capacity memory stick.

Prices are at an all time low so I figured I would browse eBay to get an idea of what to spend, and eventually settled on a 32GB USB2.0 stick for the princely sum of £12.50 including delivery. This was from a UK seller so I expected the stick to arrive fairly promptly and I was not disappointed in this regard.

First hints that something were amiss come as we examine the packaging. It's not a sealed blisterpack which would prevent tampering and the printing is a little bit, shall we say, amateurish? Of course, this may not even be the original packaging anyway.

Front Packaging Rear Packaging Memorty Stick

These things are knocked out dirt cheap in Chinese factories but you'd expect them to be able to spell and capitalise 'FLASH' by now. Or maybe I'm reading this wrong and 'FlASH' (FIASH?) is some hip thing used by the young 'uns in Guangdong province. To raise my paranoia further, the only mention anywhere of the stick's '32GB' designation is a single sticker on the drive's folding cover. Um.. yeah. In a non-tamper-proof-box.

usb stick capacity summary

The drive mounts in Windows 7 with no problems whatsoever and shows free space of 31.2GB from a (claimed) 32GB drive which is nothing out of the ordinary. Windows doesn't pop up any requests for software, additional drivers or anything like that - everything is as it should be for this stage.

Problems become apparent as soon as we test the capacity of the memory stick. To begin with I simply copied the first 20 episodes of Running Man - totalling 28.3GB - to the drive. Using Video files is recommended for these tests for several reasons:

  1. They're already heavily compressed, so any hidden compression doesn't work.
  2. They can be viewed without processing unlike, say, ZIPs, which can be fooled.
  3. Human eyes pick up any problems quickly since they're good at that kind of thing.

The files I began with were AVI files. These copied to the stick at a rate of roughly 4MB/sec - slow compared to a removable harddrive but not downright terrible.

On playback, however, there were problems. The first two files, totalling roughly 3GB, played back with no problems whatsoever. After that though, none of the files would play at all. I copied one back to the desktop from the memory stick and dropped it into Programmer's Notepad alongside the original and - sure enough - the files were completely different.

memory stick video error
Not a good start.

AVI is a container format that handles a multitude of encoding methods, so results in a file that is very hard to fake in the limited space available on a memory stick's firmware. To test further, I deleted all files from the drive, recopied the first two AVI files again and padded the rest of the drive - purposely going beyond 4GB - with some home video MPEG files. MPEG being a fairly standardised and well-known format, it's not impossible for some trickery to occur while writing the files to the stick.

   
first frame of the original video first frame of the copied video

Sure enough, odd things were happening. While the MPEG files on the stick would play, they were not playing the same video as the original files on the HD. The headers and formats of the files were intact, but the actual MPEG stream began with a random snippet from towards the end of the video, not the expected picture. In addition, any subsequent files I attempted to copy would contain snippets from MPEG files that were already present on the drive - obviously having run out of actual space on the memory stick.

So what is it?

I booted into Windows XP and fired up Flash Drive/Card Tester which identified the card as a Kingston, DT 101 G2, 8.00 - an 8GB card masquerading as a 32GB one. 8GB cards are roughly £4 right now, so £12 is a decent markup (especially if you live in China) for what amounts to popping a '32GB' sticker on there.


Flash Drive Tester starts failing at approx 10% read - or 3.2GB.

In Layman's Terms:

Every device you connect to your computer has a program running on it, called 'Firmware'. When Windows wants to know the size of a device or the amount of space remaining, it simply asks the device and the firmware responds with an answer. In this case, the firmware has been instructed to reply with fake values and Windows thinks the drive is bigger than it actually is.

The scammers know that some people will try copying 32GB of files to a 32GB stick, so they fix the firmware to respond with 'copying OK' messages and write the content of the file over the same sections of memory, while putting fake entries into the File Allocation Table (the map of used space) to make it look like the files are right there on the drive. They also know that many people will not fill the stick at the first attempt, and so the drive accurately copies the first few GB of files to give the impression it's working correctly.

This way, many customers don't realise what is happening until some months down the line. By the time they have gone back to the retailer, and the retailer has gone back to his wholesaler, the scammer is long gone and is busy trading under another new name.

Summary:

Whenever you buy a memory stick - even from a trustworthy retailer - the first thing you need to do is make sure it does exactly what it says on the tin. Fill the stick with video files and compare the two sets side by side to ensure that the files have copied correctly. AVI files are better than MPEG files for this since they're much more likely to fail, but you can play a game of 'spot the difference' by jumping to roughly-similar points in random videos and confirming that they match.

This particular stick will be going back to the seller via eBay. It's impossible to tell who is responsible for the scamming attempt since the supply chain could be quite long, but my instincts - going on the quality of the packaging - say it was someone fairly early on. Remember that you may not be the only person scammed here, and that the person selling the memory stick to you may have absolutely no idea it's a fake.

And there's more!

After returning the stick to the seller I bought a Toshiba branded unit instead. This arrived in sealed packaging that looked much more professionally produced but which suffered from the exact same problem - any AVI files saved past a certain capacity (7.4GB in this case) would be unplayable and MPEG files would play random content.

Just goes to show, you can't trust the exterior packaging of a stick to tell you what it really is. No matter where you buy it or what brand it is, you must check the capacity of any stick yourself.

 

bl0ke


Tested on desktop versions of Chrome, IE11, Edge, Safari, Opera and Firefox. Any problems are entirely your own.

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