Re: suspicious text alteration
--On February 3, 2009 6:38:19 PM +0000 linux@aleblanc.cotse.net wrote:
Hi,
I noticed something very suspicious the other day while using emacs.
I'm sure I saw a text character on my screen (far from my cursor or
mouse pointer) change to a different character on it's own.
I have noticed this a couple of times before in the past, but
instantly ignored it assuming it was my imagination.
Here is a list of possibilities I can think of:
Sounds like either bad video ram, or bad ram, or a badly behaved video
driver. To rule out bad system ram (or if your ram is shared) use
memtest86 or memtest86+, for bad video ram, I'm not sure of anything out
there to test dedicated VRAM. But if your vram is shared you can try
physically swapping your DIMMs (Eg move dimm0 to dimm1 and dimm1 to dimm0)
and testing again. Another possibility is that you've got something in
your case shorting the video bits, or a motherboard failure (there's a
bunch of well documented problems with nvidia and other bga package
systems).
I highly doubt it's anything security related.
1) I was hallucinating - it was late, but I did not feel tired,
and double checked myself.
2) Software error - I was using emacs 22.3. and did not have any
modes running that could do something like that.
3) Harware error - the machine had been running for a long time,
but is less than one year old. However there is a minor
problem - when I alter the screen brightness using the fn key
the brightness indicator that appears is usually garbage.
Sometimes it appears as normal though.
4) Cosmic rays - I have read that computer memory chips can be
altered by cosmic ray interference, and that this is not
uncommon:
http://www.newscientist.com/blog/technology/2008/03/do-we-need-cosmic-ray
-alerts-for.html
http://news.bbc.co.uk/2/hi/technology/7335322.stm
5) Hacker/Root kit - could someone disrupt my workflow by
installing a rootkit which subtly alters text? or maybe a
hacker is doing it directly? I did have an SVN server & SSH
server connected to the internet, and frequently used instant
messaging with people I don't know very well.
Can anyone give me advice? Am I being too paranoid? too relaxed?
Has anyone else had the same problem or heard/read about it?
--
aleblanc
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