Virus Total

   Highly Recommended!

 

  VirusTotal, a subsidiary of Google, is a free online service that analyzes files and URLs enabling the identification of viruses, worms, trojans and other kinds of malicious content detected by antivirus engines and website scanners. At the same time, it may be used as a means to detect false positives, i.e. innocuous resources detected as malicious by one or more scanners. VirusTotal will scan, and detect, if appropriate, any type of binary content, be it a Windows executable, Android APKs, PDFs, images, javascript code, etc.
     While VirusTotal provides a second opinion on a given file or URL it is by no means a full-fledged antivirus and it is not intended to be. VirusTotal is not available for download, it is  a web application.

VirusTotal's main characteristics are:

Free unbiased service: VirusTotal, is offered freely to end users as long as its use has no commercial purpose and does not become part of any business activity. VirusTotal does not distribute or advertise any products belonging to third parties, but simply acts as an aggregator of information. This prevents them from being subjected to any kind of bias and allows them to offer an objective service.

Runs multiple antivirus engines and website scanners: The data is the output of different antivirus engines, website scanners, file and URL analysis tools and user contributions.

Real time updates of virus signatures and blacklists: The malware signatures of antivirus solutions are periodically updated as they are developed and distributed by the antivirus companies. The update polling frequency is 15 minutes.

Detailed results from each scanner: VirusTotal not only tells you whether a given antivirus solution detected a submitted file, but also displays the exact detection label returned by each engine.

Desktop applications for interacting with the service: VirusTotal's team has released a number of desktop applications and tools for interacting with the service (one-click file uploader, browser extensions, etc.). Many of VirusTotal's users have also developed their own applications and have made them publicly available on the Internet.