Does anybody know what kinds of threats a computer (Windows XP SP2) is exposed to, while it is in standby mode, hibernating or shut off? Is it possible for anyone to access a computer when it is not running? Does Comodo Firewall Pro protect the system (I guess not, when the harddisks are off)?
The reason why I ask, is that I (and probably you, too) sometimes use the standby function (not hibernating though). My computer is also permanently connected to the Internet via a network cable. I usually unplugg it when shutting down the computer, but is it any idea to do that?
“Is it possible for anyone to access a computer when it is not running?”
Certainly not easy! And not in the usual ways. Here are some things to think about.
With physical access, they can take your hard drive and copy it. Don’t laugh, it’s the easiest way to gain access! If in an office, do you know who handles your janitorial service? That’s a common loophole.
Most computer BIOS have a little-known (and rarely enabled) feature allowing “wake-on-LAN” – i.e., if enabled, a remote user can cause your computer to start running even when it is turned OFF. 99.99 percent likely this is NOT enabled, but if you are concerned, go into your BIOS at boot time to verify.
Beyond that, however, you have little to be concerned about.
When the computer is off, it is off. Neither the hard drive nor chip-memory (RAM) have electricity going to them, and computers need electricity to run.
When the computer is hibernating, it is actually turned off. The RAM contents were saved in a special file that will be restored when it is turned back on, but for now it is really OFF. So again there’s no electricity to allow access.
When the computer is in standby mode, you have a bit more complex situation: the power is actually ON, and the RAM contents are still in memory. HOWEVER, the only thing going on is a little BIOS program that keeps the memory alive and probably makes a light blink on your laptop. None of the rest of the hardware (including the network card) has any electricity so again nobody can access the computer.
ONE FINAL CAUTION: computers often do not reliably go into hibernate/standby mode. If you push the right button (or close the lid) and walk away without verifying that it really DID shut down… it may not have gone to sleep! I’ve had batteries run down every once in a while this way. AND, if this happens, the computer spends the time fully running (but usually with some software application locked up.) In such a situation, the computer is ON, and your firewall ought to still be doing its protection job.
Thank you for the extensive answer! I guess there’s nothing to worry about then, even though two diodes flash (where the network cable is plugged in) also when the computer is shut off.