4 ms·

Everything is an input device (fun with barcodes) [video]

58 points by wlecometo 4y ago

amelius 4y ago
Any good videos/blogs that explain how barcodes (1d and 2d) are read?
- pr07ecH70r 4y ago
  I quickly found this one... till this post, I've never thought about how bar codes work. :D https://www.abr.com/wp-content/uploads/2014/04/barcode-basics.pdf https://www.abr.com/wp-content/uploads/2014/04/barcode-basic...
- cyberbolt23 4y ago
  Maybe this answers your questions https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2859730/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2859730/ or even deeper https://conservancy.umn.edu/bitstream/handle/11299/175329/Schrier_umn_0130E_16096.pdf%3Bsequence%3D1 https://conservancy.umn.edu/bitstream/handle/11299/175329/Sc...
behnamoh 4y ago
Can't wait to see equivalent NFC tricks misused at stores. Imagine doing an NFC which sends malicious instructions to your phone.
- Nextgrid 4y ago
  NFC is a bit different - it doesn't try to pretend to be an input device. There are specific protocols that NFC devices can speak and the device can parse and then display (such as for NDEF tags), but short of exploiting a vulnerability in the parser, this kind of attack isn't possible. The vulnerabilities outlined here are: 1) the barcode reader itself is configured over the untrusted channel via specific barcodes, instead of out-of-band via the USB interface 2) the barcode reader is either already emulating a keyboard, or can be configured to do so via the (untrusted) configuration mechanism described above. This vulnerability can be mitigated by making sure the barcode scanner can't be reconfigured in the field and by talking to the barcode scanner over a specific interface (serial) instead of keyboard emulation, so that data from the barcode scanner has no chance of being interpreted by the OS as keyboard input.
stragies 4y ago
That reminds me of "Ol' Bobby tables" https://barcode.tec-it.com/barcode.ashx?data=Robert%27)%3B+DROP+TABLE+students%3B+--&code=Code128&translate-esc=true https://barcode.tec-it.com/barcode.ashx?data=Robert%27)%3B+D... https://xkcd.com/327/ https://xkcd.com/327/
victorp13 4y ago
Note how these folks are moving to the next slide using a barcode scanner. Like an absolute boss!

58 points by wlecometo 4y ago

amelius 4y ago

Any good videos/blogs that explain how barcodes (1d and 2d) are read?

pr07ecH70r 4y ago
I quickly found this one... till this post, I've never thought about how bar codes work. :D https://www.abr.com/wp-content/uploads/2014/04/barcode-basics.pdf https://www.abr.com/wp-content/uploads/2014/04/barcode-basic...
cyberbolt23 4y ago
Maybe this answers your questions https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2859730/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2859730/ or even deeper https://conservancy.umn.edu/bitstream/handle/11299/175329/Schrier_umn_0130E_16096.pdf%3Bsequence%3D1 https://conservancy.umn.edu/bitstream/handle/11299/175329/Sc...

behnamoh 4y ago

Can't wait to see equivalent NFC tricks misused at stores. Imagine doing an NFC which sends malicious instructions to your phone.

Nextgrid 4y ago
NFC is a bit different - it doesn't try to pretend to be an input device. There are specific protocols that NFC devices can speak and the device can parse and then display (such as for NDEF tags), but short of exploiting a vulnerability in the parser, this kind of attack isn't possible. The vulnerabilities outlined here are: 1) the barcode reader itself is configured over the untrusted channel via specific barcodes, instead of out-of-band via the USB interface 2) the barcode reader is either already emulating a keyboard, or can be configured to do so via the (untrusted) configuration mechanism described above. This vulnerability can be mitigated by making sure the barcode scanner can't be reconfigured in the field and by talking to the barcode scanner over a specific interface (serial) instead of keyboard emulation, so that data from the barcode scanner has no chance of being interpreted by the OS as keyboard input.

stragies 4y ago

That reminds me of "Ol' Bobby tables" https://barcode.tec-it.com/barcode.ashx?data=Robert%27)%3B+DROP+TABLE+students%3B+--&code=Code128&translate-esc=true https://barcode.tec-it.com/barcode.ashx?data=Robert%27)%3B+D... https://xkcd.com/327/ https://xkcd.com/327/

victorp13 4y ago

Note how these folks are moving to the next slide using a barcode scanner. Like an absolute boss!