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Ask HN: Write-protected USB drives?
3 points by gnosis on June 19, 2013 | hide | past | favorite | 4 comments
I often need to resort to sneaker net to transfer data from machine to machine, and USB drives are usually the most convenient option for doing this on modern systems.

The problem with USB drives is that they usually offer no protection against malware infestation from the machines you plug them in to.

As far as I know, there is no such thing as a write-protected USB drive. But I'd love to be proven wrong.

I've thought of creating checksums for all of the files on my USB drive, but because USB drives are so slow, verifying the checksums every time I plug my drive in is going to be impractical.

What are the rest of you using for situations like this?



Physical write-protect switches on USB drives used to be common. I have 2 or 3 low capacity drives in a drawer with the switches.

A google search for

write protect switch flash drive

lists several drives that explicitly state they have a write protect switch.


They used to have a HW switch, but that was years ago.

I'd use an SD card+reader - SD cards still have an actual, hardware read-only toggle, and most readers will report as USB drives.


I just found an article[1], which advises that,

"SD Cards, while they have a write-protect switch, are actually no good for this purpose because it’s not actually hardware write protection – at best the card reader sends a signal to the operating system that the drive should be treated as read-only."

"It is the responsibility of the host to protect the card. The position of the write protect switch is unknown to the internal circuitry of the card."

"Basically this means that either a) cheap card readers that lack the sensor or b) operating systems or malware that don’t respect the 'please don't write to this disk' flag can write to the drive."

[1] - http://www.fencepost.net/2010/03/usb-flash-drives-with-hardw...


Use a hardware write blocker. They make them for forensics:

http://www.wiebetech.com/products/USB-WriteBlocker.php

http://www.tableau.com/index.php?pageid=products&category=fo...




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