Not many people are carting around tower computers and keyboards to hotels rather than laptops, but combined with things like how easy it is to hack WEP encryption (rather than more secure, but still crackable, WPA & WPA2) on wireless networks and so on, this is just one more way others can find out what you’re doing.
On the other hand, how much you wanna bet the CIA, et al have known about this for decades. And used it against, oh, let’s say… you.
Power sockets can be used to eavesdrop on what people type on a computer. Security researchers found that poor shielding on some keyboard cables means useful data can be leaked about each character typed. By analysing the information leaking onto power circuits, the researchers could see what a target was typing.
[...]
The research focused on the cables used to connect PS/2 keyboards to desktop PCs.Usefully, said the pair, the six wires inside a PS/2 cable are typically “close to each other and poorly shielded”. This means that information traveling along the data wire, when a key is pressed, leaks onto the earth (ground in the US) wire in the same cable. The earth wire, via the PC’s power unit, ultimately connects to the plug in the power socket, and from there information leaks out onto the circuit supplying electricity to a room. Even better, said the researchers, data travels along PS/2 cables one bit at a time and uses a clock speed far lower than any other PC component. Both these qualities make it easy to pick out voltage changes caused by key presses.
[...]
“The PS/2 signal square wave is preserved with good quality… and can be decoded back to the original keystroke information,” wrote the pair in a paper describing their work.They demonstrated it working over distances of 1, 5, 10 and 15m from a target, far enough to suggest it could work in a hotel or office.
# 20 Somebody_Else said, “Proper “WPA2″ encryption uses secure AES-based CCMP, and thus far there are no known exploits.”
If you aren’t handling certificate issues correctly you could get in by man in the middle. Not likely though.
“so each key has it’s own voltage signature? And you can tell who is typing what by the power outlet? LAME and COMPLETE BS”
Each key sends a unique signal from the keyboard to the PC. This is an electrical signal that both leaks into the ground system and radiates through space. A system used to monitor these signals would only provide a display of keys typed.
The tinfoil hat crowd has most of this discussion right.
MAC address filtering and WEP is good for preventing casual misuse – read: 95% of the people you re trying to keep out who have no hacking “tools” but will just steal your open wifi. It’ll get beat in minutes (literally, single digit minutes) by anyone with hacking tools.
WPA/WPA2 with good passwords is secure enough for protecting your porn habits from prying eyes, or whatever it you think people will care about getting into your business for.
The techniques that are technically possible – I mean, power signal leakage, freezing your memory to get encryption keys, and even the monitor signal leakage, etc — these are not the hacks of “hackers” as much as governments and industrial espionage types, maybe. You aren’t important enough to draw that kind of technological threat. The individual’s threat model is more along the lines of wifi snoopers, virus/trojan keyloggers, physical cameras, etc…
Know your threats and design your protection against them as best you can, and just accept that there’s no perfect security against a foe with unlimited resources and motivation – fortunately, most of us will never face that foe. A properly shielded cable isn’t worth a hill of beans if your wife still leaves herself logged into her computer 24/7 without locking the machine — it’d be easier for someone to break in and install a quick keylogger on her machine than to try to tap into my power line to pick out signals.
Interesting idea, though – signal leakage via improperly shielded cables. Cool.