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Lecture recording on may 14

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From: Christopher M.
Date: Sun 24th May 2020, 7:34am


"Lee de Byl" <10*0*8*[email protected]*u*e*t*u*a*e*u*a*> wrote:

> Ah, that's interesting. I had wondered if having the shell scripts as standalone files would also more easily permit some type of race condition exploit, where the contents of the files could be changed in between having their contents verified, and being executed?

[all other readers can safely ignore this reply]

There's certainly a set of race conditions there, but probably quite difficult to get that 1 in 10000 chance to catch the time window during the reboot sequence.
Another approach could have been to open each script (file), fork new processes, set the trace bit in the children, exec the scripts (which will immediately pause them, giving
control back to the parent), then checksum the scripts before resuming their execution.  Remember that first opening a file means that a process retains access to the original/opened
file, rather than any future changed instance of it.

Related articles

Lecture recording on may 14 (all 6) RSS
├─ original   Thu 21st May 2020, 6:54pm, Deepakraj S.
├─ reply 1   Fri 22nd May 2020, 7:39am, Christopher M.
├─ reply 2   Fri 22nd May 2020, 11:58am, Lee dB.
├─ reply 3   Fri 22nd May 2020, 12:32pm, Christopher M.
├─ reply 4   Fri 22nd May 2020, 1:46pm, Lee dB.
└─ THIS   Sun 24th May 2020, 7:34am, Christopher M.
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