Unfortunately Virustotal can only help you with already known threats and viruses by comparing the code to known threats. If you are unlucky and download a file that contains a fresh code with a virus then Virustotal will not be able to help you since it is the first time they see the code. The results can come back as clean while in fact you get infected and if you do a 2nd scan in a few days you see that some antivirus engines are already registering the file as a threat.
This is why I wrote those recommendations.
Notes:
- Please remember that this one is a free online service, it should be used only as substitution of professional antivirus or internet security softwares for someone who don't have those softwares on their devices (lack of money, or anything else).
- You all should protect yourself better by spending money to own antivirus or internet security softwares on your devices.
- It is very cost-effective investment for your assets.
Virustotal, and other online virus scanning sites, should only be used for people who don't have money to buy professional softwares.
For someone, who already own professional softwares, they obviously can use those sites as supplementary stuffs to make pre-scan before downloading files and scan again by their softwares.
Your recommendations do not mentioned what Pmalek said.. in any word.
Virustotal
and any other AV software can only recognize malware by 2 approaches:
- Heuristics
- Behavior analysis
Regarding Heuristics:
If the malware is either 1) new or 2) modified so that these AV's don't have it in their database yet -> No Heuristic to match the malware with.
Regarding Behavior analysis:
If the malware does not run malicious code when being analyzed (can be done with multiple techniques, e.g. checking whether being run in a sandbox) -> Not triggering the behavior analysis.
Now, if we combine these two statements, it becomes clear that it is quite easy to create malware which is completely undetected from AV's (at least until enough people have been infected with it and AV's have manually reviewed and sigged the malware as such).
Using AV's (whether paid ones on your computer, or online services like virustotal) does only protect you against 1) known and very wide-spread malware and 2) malware created by script-kiddies or any other non-commercial cyber criminals.
