Detection Problem

[David Rak 0]

Hi, I have a batch virus, I trying to open it on Virtual Machine, It destroyed my whole computer on Virtual Machine but my real computer was safe, When I scanned the batch file, ESET Antivirus was saying it it's safe, I was sended file for analysis but I don't get any reply from ESET about that, It was 2 months ago, I am rating ESET for five stars but this need be fixed, the batch file basically was killing explorer.exe process including deleting system32 and other files. Please reply why?

[Marcos 5,074]

Please provide the subject of the email that you submitted to samples[at]eset.com.

Batch files and basically scripts in general can be created in millions of ways. Especially if they are very small and run only system commands, it may be even impossible to detect them because some users might use them for legitimate purpose. Example: assume a batch file that adds a new user through the system net command. On one hand, it can be a part of a malicious batch file, however, on the other hand it can be used by administrators for perfectly legitimate purposes. And even if a detection is added, malware writers can obfuscate it in many ways or even wrap it into an executable (that can be again obfuscated / protected) to evade detection.