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Authored by: Anonymous on Monday, June 25 2012 @ 01:30 PM EDT |
> once the OS is compromised, it will no longer boot,
> as it should no longer match it's signature
Are you sure about that? I thought it was just the bootloader that was
"protected" in this way.
If the boot sequence has to signature-check the entire OS, running Windows
Update might take a wee while...
[ Reply to This | Parent | # ]
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Authored by: BitOBear on Monday, June 25 2012 @ 11:12 PM EDT |
False. (Well false-ish).
Each component in the chain must be "good" as far as the -previous-
component is concerned or that previous component will not invoke the next. So a
signed boot loader can boot signed or unsigned code at it's whim.
Each component can check that the previous components were properly signed and
then act or refuse to act at its whim.
In the case of an "OS" however, once the kernel is loaded things like
configuration files can cause all sorts of damage. If MyTrojan is inserted into
the list of system services then MyTrojan will run and the system will be
compromised.
So this cuts down on "viruses" (which is a very specific kind of
thingy where actual executables are patched to attach extra code, in the same
way that biologic viruses co-opt cell reproductive mechanisms by installing new
RNA/DNA into the cell) but it doesn't particularly cut down on any other kind of
exploit.
Unless every single file and application is saved from top to bottom, right down
to the script and batch files you use to automate your system, then there is a
chance for exploit.
There is a lot of money to be had in selling "signing services" and
there's a lot of annoyance to be paid by users.
Forcing signing "deep enough" to be effective is onerous if the local
machine cannot sign its own additions, and it can be made ineffective if it
-can- sign its own additions.
Also system and application program start time increases as signing goes
deeper.
Its a money grab -and- a set-top-boxification of computing.[ Reply to This | Parent | # ]
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