A cheap barcode scanner helped fix CrowdStrike'd Windows PCs in a flash
1–10 of 23 posts
Re: A cheap barcode scanner helped fix CrowdStrike'd Windows PCs in a flash
#2saved you a click: they used barcode scanners to automate entering the bitlocker recovery code, which is different for each machine and is required during the removal process.
Re: A cheap barcode scanner helped fix CrowdStrike'd Windows PCs in a flash
#3saved you a click: they used barcode scanners to automate entering the bitlocker recovery code, which is different for each machine and is required during the removal process.
To expand on it: they converted the recovery codes to barcodes, and used the fact that the scanner works as a keyboard, to scan the codes off the screen and input it to the correct machine (the machine where the scanner is plugged into)
Reminds me of someone experimenting with a public transport vending machine that had a barcode scanner (IIRC because you can scan an old ticket to purchase the same type of ticket, e.g. weekly ticket, etc), he made barcodes which encoded control keys to see how the computer behind it would react.
Re: A cheap barcode scanner helped fix CrowdStrike'd Windows PCs in a flash
#4MS needs to legitimize this hack ASAP. Bitlocked drives are the biggest time bottleneck for every IT tech. They're usually working with scraps of paper taped to keyboards.
Re: A cheap barcode scanner helped fix CrowdStrike'd Windows PCs in a flash
#5saved you a click: they used barcode scanners to automate entering the bitlocker recovery code, which is different for each machine and is required during the removal process.
To expand on it: they converted the recovery codes to barcodes, and used the fact that the scanner works as a keyboard, to scan the codes off the screen and input it to the correct machine (the machine where the scanner is plugged into) Reminds me of someone experimenting with a public transport vending machine that had a barcode scanner (IIRC because you can scan an old ticket to purchase the same type of ticket, e.…
I've seen a communal machine with a long IT policy compliant password and logout timer with the account avatar set to a QR code of the password and a barcode scanner provided.
Re: A cheap barcode scanner helped fix CrowdStrike'd Windows PCs in a flash
#6[deleted]
Re: A cheap barcode scanner helped fix CrowdStrike'd Windows PCs in a flash
#7[dead]
Re: A cheap barcode scanner helped fix CrowdStrike'd Windows PCs in a flash
#8Interesting idea, but keep in mind that older laser-based barcode readers don't work when reading from an LCD screen
Re: A cheap barcode scanner helped fix CrowdStrike'd Windows PCs in a flash
#9saved you a click: they used barcode scanners to automate entering the bitlocker recovery code, which is different for each machine and is required during the removal process.
To expand on it: they converted the recovery codes to barcodes, and used the fact that the scanner works as a keyboard, to scan the codes off the screen and input it to the correct machine (the machine where the scanner is plugged into) Reminds me of someone experimenting with a public transport vending machine that had a barcode scanner (IIRC because you can scan an old ticket to purchase the same type of ticket, e.…
> he made barcodes which encoded control keys to see how the computer behind it would react.
Crazy, I didn't think that was possible, turns out at least Code 128 can map all of US-ASCII [1]. Wonder how the control characters translate to keyboard keycodes internally.
Re: A cheap barcode scanner helped fix CrowdStrike'd Windows PCs in a flash
#10saved you a click: they used barcode scanners to automate entering the bitlocker recovery code, which is different for each machine and is required during the removal process.
Keyboard wedge barcode readers have a long history in data entry in industrial settings.
One of my current Customers uses the UPC on the finished goods they make to "program" the PLC on their production line with the parameters of the finished good. The barcode reader is just "typing" the UPC and various commands into a serial-to-Ethernet gateway that's ultimately connected to a TELNET server on a PC w/ PLC software in it. Slick, if not a bit glue-and-tape (and kinda terrifying from a security perspective, albeit it is in a fairly well-isolated and filtered network segment).
I've seen an ERP system that printed command barcodes onto the paper "routers" accompanying physical parts around the shop. Workcenters scanned barcodes that "typed" the commands to drive the work-in-process job tracking into a PC running the client app. They used a prefix character as an attention sequence that could invoke menus then return the user back to the "screen" they were previously in. It was fun to type these on the keyboard directly.
I also supported a terrible application that used keyboard wedge barcode readers for "two factor authentication". Each user had a card with a code 128 barcode the vendor provided to scan as their "second factor". (The Customer showed the vendor how photocopies of the cards worked to "authenticate" after I pointed it out. The vendor replaced it with TOTP. It's all pointless because the app is based on shared-fike access to DBF files via a compiled Visual FoxPro application running on each client PC. I wish I was kidding. I also wish this application wasn't used for a very important and security-sensitive function, too... >sigh<)