I’m running 64 bit Windows Vista Home Premium, and probably being paranoid, but after installing a program from a CD my friend provided and attempting to run it, my antivirus software (AVG Anti-Virus Free) detected something called Trojan Horse Generic13.OPT. I used the Heal option as a power-user, which seemed to work, as AVG isn’t bothering me about it anymore. However, since I can’t find any information on this particular trojan, I was wondering if someone could tell me a) What this particular virus is supposed to do, and b) How I can be sure I got the thing out of my comp, beyond running regular scans with AVG?
- Sounds like you’ve got some pirated software, it’s quite common for cracked .exe’s to false-trip AV software-- a true threat may or may not exist.
- Run a check with MalwareBytes
- Run a check with Avira
- The only way to guarantee removal of a virus is a format + reinstall of the OS.
Scan again if it doesn’t detect anything your fine. If you are really paranoid then flash your BIOS, and reformat your computer. Keygens have lots of false positives if that is what in fact you were doing
And 99.9999% of the time, this is never necessary. It’s burning down the house to get rid of a mosquito – effective, but not the best way to fix things.
Anti-virus software is supposed to be, well, antivirus so if you clicked on the right things when it came up, you should be fine. I hit the same thing a few days ago with a Trojan. Reformatting your computer and flashing the BIOS is pretty damn extreme. I wouldn’t consider it unless you notice things get really bad and I am a software professional with 13 years of experience. If you remain paranoid, you could uninstall AVG and switch to another anti-virus software package like AVAST and do a full scan. It is possible that the two programs are slightly different and would pick up something that the other one didn’t but I doubt it. I like AVAST better than AVG these days but both should be effective. The fact that the software caught it is a good thing and that should have taken care of the problem.
Yeah, well, 99.9999% isn’t 100% now is it? The answer was in response to the question “How can I be sure it’s gone” and this is really the only way to be sure!
Authors of viruses generally do not get very sophisticated with their coding, owing to the relative stupidity of the general public and the eagnerness to open unknown attachments and surf the web for free porn and warez and not keeping security black holes like Flash, Acrobat and MSIE and even the damn OS up to date with security fixes.
A relatively mundane virus can easily take advantage of security exploits within one’s own AV software (a particularly nasty piece of kit was able to uninstall Avast without any input from the user-- the easiest way to see it was gone was to notice it missing from the taskbar), or embed itself elsewhere on one’s hard drive, or embed some registry keys that AV software may or may not be able to detect.
A sophisticated virus with access to the kernel could ostensibly even make its way out of a virtual machine instance, but again, virus coders are not going to be wasting their time coding up some malware aimed at defeating VM instances when the vast majority of people that get viruses don’t even know what a virtual machine is.
IMO AVG is the ZoneAlarm of protection suites, certainly it’s not all it’s cracked up to be, but the bottom line here, irrespective of whether a format is “too much cure” is that 1) using a modern router with its own firewall and 2) responsible internet usage habits will defeat 99.9999% of malicious intrusions.
Thanks for your help, everyone! I did a system restore from a few days ago just for fun, and since AVG seems happy, I’m not going to go through the headache of reformatting, since the thing appears to be well and truly gone. In any case, thanks a lot! 
AVG will usually tell you if it can’t clean a file out completely.
You might want to uninstall AVG with revo uninstaller and then put AVAST on and run it again and see if AVAST comes up with anything. If not, then you’re pretty safe.
You can’t really run two anti-viruses on your computer at the same time, 'cause they usually conflict. (Perhaps you can, but if you try and fail this is the reason)
You can try a registry cleaner though if you don’t know what you’re doing you can often do more damage than it’s worth.
Hmm, for registry-related stuff the only thing I’ve been doing is using CCleaner to Scan For Issues every so often. I suspect that the trojan thing was either a false positive or easily dispensed with, but I thought that I’d be better off asking because of all the horror stories my friends have told me about viruses evading AV programs, stealing personal data, and all sorts of other alleged nefarious things that I can have a ball getting paranoid over.