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Re: arbitrary code execution on unformatted usb stick



Am 25.04.20 um 15:38 schrieb Elmar Stellnberger:
Dear readers of the debian-security mailing list

  The first time I had lost my new coreboot i7 notebook when I plugged a vfat formatted usb stick into the notebook run merely offline where I developed the a̅tea. Suddenly low level operating system errors appeared and since a power off/power on it refuses to boot from any media: internal m2 and usb. The notebook is thus unusable. I have sent the computer for repair but I got it back in the exactly the same condition. If you like you can read https://www.elstel.org/uploads/laptop-note.pdf. It contains an error description (I have written it with my typewriter and the company scanned the document).   Consequently I thought that there would be an arbitrary code execution bug in the vfat file system. I prepared an USB stick, created an msdos partition table with 7 partitions and used tar to read and write from the partitions (20-blueusb.rules). However it turned out sooner and later that this also caused arbitrary code executions. It made my offline Debian installation where I run an Apache server to create content for elstel.org several times unusable. I simply could not believe it. A program as simple as tar should not contain an arbitrary code execution bug! There was no other way the system could get in touch with the outside so the usb stick was definitely at fault.   Today I have finally used cat and dd to stitch three text files together and read them back from a partition. That way I have avoided to use tar. It was on my most secure system which normally does not have any contact to other computers at all because the system with the Apache server for elstel.org was unsuable for another time. And see there I got the exactly same result without tar: After unexplainable operating system errors the system does not boot as soon as any SATA drive is attached. Flashing the BIOS does not help against this kind of error as there is also other firmware. I have seen 3 of my Kingston USB readers manipulated to not read a certain sdcard while 3 other readers of the same type and same shipping locked in a box did still read it (sdcard blue ray image to install a clean Debian10). Obviously the firmware of that device was altered. As with the USB card reader a computer has many devices each with its own firmware which can be altered to damage a computer.   This time I am at loss. If I can not plug in an USB stick there is apparently ¿almost? no safe way to communicate with that computer. There needs to be an arbitrary code execution bug hidden in the kernel which gets executed as soon as a partition table is read in. As I do not have any filesystem on that USB stick and I have automounting disabled that should not be due to filesystem probing. As my experience with bug reporting at the Firefox browser I am quite sure at least some of them are bought by secret services due to their unwillingness to fix flagrant bugs. However I would never have believed this could be the case with the Linux kernel. A kernel developer could perhaps help me if he said what code exactly got executed on plugging in an USB stick. Finally I would need to use another operating system but I can´t as there is no other distribution than Debian which offers a blue ray image for offline installation. Downloading singleton files in a batch via tor is conspicuous to secret services and thus not viable. They would simply alter the download as they have done many times. I wonder how the people at the Iranian nuclear progam do their things?

Yours Sincerely,
Elmar Stellnberger


On from the beginning I had been in doubt about the conclusion of what I reported in my last email. Such a bug in the usb mass storage driver of the Linux kernel would be extremely hard to hide. From what I believe now that supposed bug does not exist. Very likely they have a remote control of that offline PC used to maintain elstel.org. They are badgering me there too. I already had that with a previous offline computer which is of another model/make. I know it for sure with that computer since they have hindered me there to program a̅tea. I know it from other occasions as well. They knew on my online computer what I was doing offline before. Impossible if they have no connection. It is for them exactly the way as if that computer were online connected with a LAN cable or Wifi. They can do everything there. There was nothing apparently visible on the mainboard but electronic components are small and a component could have been replaced. This time it was most likely before I have received the mainboard and assembled my computer. Consequently as there is no one who would help me and even no one whom I can meet in person who would be interested in what I have to tell from 2011 I will have to give up my security related engagement. Just telling other people about what has happened could help a lot (You remember my German email from last time?). There is for sure a bug in the vfat driver. My System76 notebook was clean as otherwise they would never have left me develop a̅tea on it up to the state in which the tool is at the present time. However there are some things that would need to be done for a̅tea. That DoH/DoT shit in libunbound has an arbitrary code execution bug which concerns a̅tea every time you do not state the server certificate on the command line. You can download the server certificate securely with dig or drill so the tool is basically already fully functional. I would replace libunbound with direct system calls for DNS and verify the trust chain up to the final RRSIG manually by the program. If that condition was met, a̅tea would be fully secure and functional. We have also been talking about missing DANE support for web browsers. I know an easy-to-implement workaround: A https proxy with a Firefox-local configured certification authority. It would forward DANE-enabled sites 1:1 with self-generated certificates. Something that would work for all browsers you can think of. Unfortunately I have no way to implement that as the ultimate defenders of our freedom would simply turn my computer off if I attempted to program anything the like. This is bitter truth!






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