There are several online scanners available such as Virus Total to scan files with dozens of antivirus engines. IObit has recently started a cloud based service named IObit Cloud to analyze files for virus, malware, and other security threats.
According to the official page, IObit Cloud is an advanced automated threat analysis system. It uses the latest Cloud Computing technology and Heuristic Analyzing mechanic to analyze the behavior of spyware, adware, trojans, keyloggers, bots, worms, hijackers and other security-related risks in a fully automated mode.
Using this service is pretty much simple. Just click the browse file button to browse to the file that you want to scan and click open to upload, scan, and generate the report. The scan report displays threat type, file name, size, MD5, SHA1, and file type.
Unfortunately, the home page doesn’t provide much information about the free service.