What type of compressed files are supported?

You can submit any compressed file that is supported by the 7z software. If successfully decompressed, the contained files appear as bundled files in the relationships tab of the archive file report. If the archive is password protected, VirusTotal tries standard known passwords such as "infected" or "password".

If a password-protected archive contains a single file, the web interface will request a password (when using the API, the password parameter serves the same purpose). In that case VirusTotal scans and generates a report for the contained file rather than for the archive itself. This password-protected scanning path is limited to a 3 MB archive: if the password-protected archive is larger than 3 MB, the submission is rejected with a "maximum file size exceeded" message. To scan a larger file, extract it and upload the file directly (the general upload limit is 650 MB).