It is possible that Mozilla Firefox may get infected with virus, spyware, threat. Even though continuous support is provided by Mozilla Firefox team during the continuous updates and it is ensured that Mozilla Firefox is not easily bugged by these harmful elements, it is essential that customers install a good antivirus in the computer in order to ensure complete and better protection. It would be best to install an antivirus which is supported by Mozilla Firefox and goes with the configuration of your computer. You can call Mozilla Firefox customer support and learn from them which anti-virus would be the most suitable for the operating system you have and is compatible with Mozilla Firefox.