Viruses and compressed files...?

[PsyMan]

Do you think that your computer is protected against viruses? Do you make virus scans often and everything seems fine? Beware!!!
I recently had to take some files from school and copy them to my computer. I was aware that one of the files was adware but it was necessary. Due to the lack of a recorder I had to make a compressed zipped archive of two parts and use 2 floppy disks. The "problem" was that after copying the first part of the archive to the hard disk of my PC I checked it for viruses but forgot to copy the second part of the archive in the same directory! What the result was? Norton antivirus [highlight]CRASHED[/highlight] without detecting the "infected" file! Of course, after I placed the second part in the same directory as the first the check was made and the "infected" file was found. After that I made a "test"; I deleted one of the parts, checked the directory where the file was and all the computer but NAV crashed again when making both of the tests (due to the corrupted file).
After making some research I found that most of the widely used antivirus programs have problems detecting viruses in corrupted (single and splited) compressed archives. So if a virus pops up from nowhere or your antivirus seems to act weird... Beware!

 

[ScottJC]

Zip files are not a threat as long as you don't extract them, test them using the test button, if its curropt, delete it, it shouldn't execute code at this point.

I've only ever seen 1 virus on my system in all years in computing so I am fairly confident that I can handle anything. besides I don't do anti-virus's in the background, they waste performance.

That one virus wasn't even on my computer.

I honestly believe if you get a virus its due to your own stupidity 90% of the time, opening attachments, downloading cracks, etc.. it really is your own fault so to speak, you have to be careful. (when I say you i mean all those out there who get them)

If i manage to unzip a file, thats when I scan for viruses.

 

[PsyMan]

If you consider that the adware file in the corrupted archive could be extracted (the archive was not solid) there is a tiny possibility that a virus can be executed when you open the archive. The real problem in my case was the crash of NAV because even if there is not a virus in a corrupted archive NAV will crash because of it and even if it finds any other infections from the scan it will not give you the chance to find which file is infected (nor delete it of course).

 

[ScottJC]

Thats a load of rubbish, Zip's are not executeable data, their just files with data inside which winrar/winzip whatever reads, it doesn't execute crap. thats like saying a txt file executes data.

*opens txt file... OMFG! *your system has now been taken over by the mAst3r haxx0r!**

I don't use NAV, i think its rubbish.

What do you do with a curropt archive? recycle bin.

As for splitted archives, extract them if you want, it shouldn't ever execute the file this way unless you've double clicked the file in winrar or whatever you use.

Plus it was a School computer, its equally likely the school computer is what put the viruses on your floppys.. think about it.

 

[ScottJC]

Another thing came to mind, perhaps nav crashed but that doesn't nessicarily mean you're infected, put NAV back on and delete the archive in question, scan again, what's your virus count?

 

[PsyMan]

/me slaps ScottJC
My computer is not infected. NAV just scanned an adware file (like the ones that come with many freeware programs). My intention was to point that many antivirus programs (not only NAV) have problems with corrupted archives that may lead to some other problems. This is not a reason to start bitching about NAV, the way your PC might be infected etc.

 

[ScottJC]

then l fail to see the point of this thread, if this thread is NOT about being infected what the hell is the point? a curropt file can crash an anti-virus program? big deal, delete the curropt file and restart anti-virus, no harm done.

But then again, I don't see Zip files as a threat so I don't have AV running in the background at all, if its curropt winrar tells me, so it goes in the bin, i'm happy, my system is still alive, my method's worked for years.

The only thing I do not trust is Self extracting archives, especially with no icon, they are asking for trouble, they go in the bin straight away if they have no icon.

 

[Doomulation]

He's saying "don't do this, it might get you infected." duh.
In any case, running an anti-virus in the background is NOT waste of performance. Think what you will, but it is for your own security.

 

[ScottJC]

Yeah but there is a lot of things you shouldn't do on a PC to not get infected, for one never download attachments on emails which I find infinitely more useful than this tip.

Anti-virus in the background is fine, but since I can spot a virus a mile away I don't need it on, I usually scan once a month, i'm either very lucky or I am a human anti-virus, you only need to do it every so often. Everyone has their own way of dealing with viruses, I tend to just not do 99% of activities that cause viruses in the first place. saving me valuable cpu time.

bottom line, if you don't want viruses, don't go to dodgy sites, don't use Internet exploder, don't use outlook, don't use kazaa, don't download attachments, don't trust anyone... etc...