-: Symptoms of Infection.
How do you know your computer
has been infected with malware?
Well, the most common thing is to notice
that it starts beginning to act strange.
That could be a myriad of different things, though.
For example, your computer might start running
slower than normal.
Why might this occur?
Well, if you have a worm for example,
it's using up processor resources and network resources
to spread itself throughout the system
and throughout the network.
If you happen to be getting spam,
that again is something that's going to tax your system.
Lots of different malware will start making your computer
act slower than normal.
And this is one of the indications that you have a problem.
Another symptom of infection
is that your computer starts locking up
or stops responding to you frequently.
Maybe you're seeing more 'blue screens of death'
than you've ever seen before.
Well, this again is something
that is a common symptom of malware.
If a virus goes in and overwrites a critical system file
by mistake, that can cause the computer to crash or lock up.
This brings us to our third thing.
If your computer restarts or crashes a lot,
this again is another symptom that you may have
a malware infection.
Next, if your hard drive, files, or applications
aren't accessible anymore, this could be a symptom
of a malware infection.
Because if a virus or piece of malware takes over a file,
it's going to change its permissions.
And by doing that, it can remove your permissions
that allow you to run it or delete it or change it.
This is one of the ways that the malware will keep
persistence in your system.
Another symptom of malware
is if your computer starts to make strange noises,
or you start to see unusual error messages,
or your computer, the display starts looking strange,
or when you print something,
it looks like gibberish or gobbledygook,
and it uses symbols instead of normal letters.
All of these things can happen
when you get a virus or you get malware,
depending on the way the virus or malware
starts infecting your system.
Another sign that you might have an infection
is if you start to see new icons appear on your desktop
or conversely, icons from your desktop start to disappear.
Again, as any additional programs are added,
new icons might show up, and if you start deleting programs,
that can remove those as well.
Another way that malware tries to hide itself
when it's in your system is by using double file extensions.
This is because in Windows, by default,
if there's a known file extension,
such as .exe for executable, or .txt for text files,
that part won't be shown on the icon's name.
So if you have something that says
textfile.txt on your desktop,
it could have a hidden .exe at the end of it.
And when you double-click that file
that looks like a text file,
it's actually going to run this executable file.
And that can actually embed malware
into your system even further.
Another symptom that you may have had something bad happen
is if you try to run your antivirus software
but it just won't run.
A lot of malware is programmed
to attack your antivirus software,
and that way it can prevent it from running
and maintain persistence longer.
The reason for this is that malware
doesn't want to be taken out of your system.
And if you're able to run your antivirus
you might be able to clean up the malware.
But if they can attack your antivirus
and keep it from running, that means that they can
stay on your computer for longer and dig in deeper.
Yet another symptom is when your files or folders
are corrupted, or you may see new files and folders
that have been created.
Again, as a piece of malware goes and infects your files
this corruption can make them be deleted,
or it'll create new files for it to hide in.
Again, the malware might do this as a way
to maintain persistence and dig in deeper into your system.
And this can add new files that get infected
and those files might be put across the network.
The final symptom is if you try to go
and use your system restore function within Windows
and you can't do it.
Because again, similarly to what I talked about
with antivirus being turned off by malware,
malware is going to try to turn off your system restore,
because they don't want you to be able to go back
and restore from a known good backup.
In this way, malware again
is trying to maintain that persistence.
All of these things are really summarized quite simply
with one simple statement.
If your computer is acting funny or strange,
you may be infected with malware
and so it's best to boot up into safe mode
or boot from an external drive
and then scan your computer with a good antivirus software.