Strictly speaking, myetherwallet.com this is not a wallet.
Cryptocurrency may be stolen due to user negligence. In most cases, even the antivirus will not help save the user's funds. We need to be careful, a lot of phishing links and sites.
Antivirus is only one item from the General security list of your devices and data. Therefore, it is necessary to take into account all possible ways of hacking and theft, because the human factor makes it possible to make mistakes.