Live Ubuntu USB drives are used for the purposes of secure transactions e.g. banking, payments,etc in the absence of live CDs since the devices do not include CD or DVD-ROMs.

Since there are regular patches being published and the USB drives have limited storage, what is the best way to ensure the applications being used e.g. browser, shell, etc are updated without attempting to update the entire base?

Is there another way to perform similar tasks to reduce the attack vectors as opposed to using live Ubuntu USB drives

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    I'm having trouble seeing what problem you're trying to solve here. – Mark Nov 19 '14 at 8:03
  • what is your problem ? Do u want to protect usb drives from outside attack ? – Arunprasanth KV Nov 19 '14 at 9:24
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    @Mark - The first problem being updating the live USB drive when space is limited. Secondly, if that is deemed difficult, what other options are there? – Motivated Nov 19 '14 at 16:45
  • @Arun Prasanth - See my response to Mark – Motivated Nov 19 '14 at 16:46
  • In my experience, updates don't substantially increase the amount of disk space used. – Mark Nov 19 '14 at 20:52

The value of a Live USB or Live CD for secure transactions comes from the fact that they create a non-persisting in memory system based on a read only ISO image. That prevents all malware attacks to the local file system from being effective beyond the single session of the attack.

Upon reboot nothing from any previous session exists as it is all recreated again from that same read only ISO image that started previous session in memory. That fact also prevents patching of a Live USB stick. While the system might act as if it were taking a patch during the session there would be no persistent change in the media thus no updated behavior on the next boot.

You are right to want the latest browser etc. for your session so you are faced with two choices. You could update your browser every time you boot knowing it would not persist or you could periodically update your ISO image by creating a custom Ubuntu Live USB using their tools and instructions.

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  • So if a Live USB is created with a partition to save files, will this not create persistent storage? – Motivated Dec 13 '14 at 6:45
  • If you routinely mount external storage or a partition on your bootable thumb drive you create a place for malware to persist and defeat the a significant portion of the Live CD/USB protection. – zedman9991 Dec 15 '14 at 21:56
  • Hi, perhaps the most important "Live USB device" for purposes of secure transations is Tails (!). And there are no problem with upgrades: tails.boum.org/doc/first_steps/upgrade/index.en.html – Peter Krauss Mar 15 '17 at 15:46

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