Malware Dropped Through a ZPAQ Archive

[...]

The file was called "Purchase Order pdf.zpaq" (SHA256:1c33eef0d22dc54bb2a41af485070612cd4579529e31b63be2141c4be9183eb6). The fact that the archive is using an "exotic" compress algorithm, the VT score is null! I tried the classic tools on a stock Windows operating systems, including 7Zip and no one was able to decompress the archive. This is a strange because it reduces the number of potential victims! On Windows, you can use PeaZip.