Can't shut down the computer

[chesters1]

50-50 says one of you is right

 

the mobile versions of windows are stored on the chips so technically a virus could co-exist after power down but our desktop / laptop versions are software based ,but (very small but) technically a virus "could " exist as just a few k on the bios chip if theres room ,pretty ineffectual though as its so small but could be a switch to allow a software virus to be switched on thats hiding somewhere on your hard disk .

Edited February 18, 2011 by chesters1

[corydoras]

50-50 says one of you is right

 

the mobile versions of windows are stored on the chips so technically a virus could co-exist after power down but our desktop / laptop versions are software based ,but (very small but) technically a virus "could " exist as just a few k on the bios chip if theres room ,pretty ineffectual though as its so small but could be a switch to allow a software virus to be switched on thats hiding somewhere on your hard disk .

A virus staying resident in RAM is a physical impossibility, but after doing a bit of digging I found that there ARE BIOS viruses out there.

 

http://www.tomshardware.com/news/bios-viru...kdoor,7400.html

 

The only way to get rid of them would appear to be a re-flash of the BIOS and a re-install. It seems like there might be some viruse that can 'HIDE' in your PCs CMOS. Clearing the CMOS by shorting it with the jumper or DIP switch on your motherboard would kill them ( I think).

[chesters1]

clearing the cmos though only usually puts the default settings back i expect .Flashing would remove the entire bios but i'm sure because they are flashed within the powered up PC real clever bad people would have it sitting somewhere waiting to jump in using the flashing program !

Nothings really secure despite what people say but i dare say these viruses would be more aimed at computers with something to gain by doing so ,i doubt they are floating around seeking every bios to live in?

flashing using a programmer and board would give a clean flash though

Edited February 18, 2011 by chesters1

[kirisute]

clearing the cmos though only usually puts the default settings back i expect .Flashing would remove the entire bios but i'm sure because they are flashed within the powered up PC real clever bad people would have it sitting somewhere waiting to jump in using the flashing program !

Nothings really secure despite what people say but i dare say these viruses would be more aimed at computers with something to gain by doing so ,i doubt they are floating around seeking every bios to live in?

flashing using a programmer and board would give a clean flash though

 

your right..a clear cmos procedure does just replace existing settings with a factory default. The only way to clean CMOS utterly is to re-write it with an upgraded firmware (flashing).

most of the time this is done via a usb pen or a floppy fisk...more advanced motherboards now offer the ability to look in the route of the C drive for the bios firmware though so it can be done a bit more easily. It is feasible to have created a virus that would infect the new firmware you are putting into the bios..but in order to seed that you would have to infect the firmware itself before installation to the bios...which would mean hacking a major provider of the firmware like Asus, or Asrock or whatever. on top of that the virus would have to work outside of the OS and also exist in a very small state to be able to be kept small enough to actually be part of the bios firmware. most are only about 900k in size when you download a new bios firmware!

ive never heard of it being done.

essentially when you flash BIOS you are creating a brand new CMOS chip....all your settings are lost, and replaced with a new advanced and tweaked version from manufacturer...its a process that we see replicated in mobile phone software upgrades etc. a CMOS doesnt not form the baasis of an OS though..so a virus resident within it would be severely limited..ok it could disrupt the power supply to HDD units or change the real time clock etc etc but beyond that it couldnt leap from the BIOS to the OS to reak havok!

primary use of virus activity these days is to grab personal data....to do that you need to be in a enviroment that the user will be creating data within..ie the OS. hence you really dont see BIOS resident virus' these days.

[corydoras]

your right..a clear cmos procedure does just replace existing settings with a factory default. The only way to clean CMOS utterly is to re-write it with an upgraded firmware (flashing).

most of the time this is done via a usb pen or a floppy fisk...more advanced motherboards now offer the ability to look in the route of the C drive for the bios firmware though so it can be done a bit more easily. It is feasible to have created a virus that would infect the new firmware you are putting into the bios..but in order to seed that you would have to infect the firmware itself before installation to the bios...which would mean hacking a major provider of the firmware like Asus, or Asrock or whatever. on top of that the virus would have to work outside of the OS and also exist in a very small state to be able to be kept small enough to actually be part of the bios firmware. most are only about 900k in size when you download a new bios firmware!

ive never heard of it being done.

essentially when you flash BIOS you are creating a brand new CMOS chip....all your settings are lost, and replaced with a new advanced and tweaked version from manufacturer...its a process that we see replicated in mobile phone software upgrades etc. a CMOS doesnt not form the baasis of an OS though..so a virus resident within it would be severely limited..ok it could disrupt the power supply to HDD units or change the real time clock etc etc but beyond that it couldnt leap from the BIOS to the OS to reak havok!

primary use of virus activity these days is to grab personal data....to do that you need to be in a enviroment that the user will be creating data within..ie the OS. hence you really dont see BIOS resident virus' these days.

No code that was in the CMOS or in the BIOS could be executed from their in any of the full 32 bit windows platforms, or under any 32 bit Intel/AMB Linux. Some other code already installed on the computer would need to copy it out of the BIOS or CMOS into an executable onto some random access storage in order to execute it.

[kirisute]

No code that was in the CMOS or in the BIOS could be executed from their in any of the full 32 bit windows platforms, or under any 32 bit Intel/AMB Linux. Some other code already installed on the computer would need to copy it out of the BIOS or CMOS into an executable onto some random access storage in order to execute it.

 

yep

Edited February 19, 2011 by kirisute