SourceUSB 3.41 was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this software available.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. The following versions: 3.4, 3.3 and 3.2 are the most frequently downloaded ones by the program users. This tool was originally designed by SourceQuest, Inc. The software is included in Internet & Network Tools. The default filename for the program's installer is SourceUSB.exe.
From the developer:
SourceUSB is a software-only USB analysis tool. It is installed on a Windows operating system as a kernel-mode driver and user-mode application. The analyzer driver coexists with the Windows USB driver stack.
Since USB is a host driven bus, viewing USB activity from the host perspective is a valuable complement to viewing USB transactions on the bus with a hardware analyzer.
SourceUSB installs easily from a Windows Installer package.
You may want to check out more software, such as PageScope Network Setup, Veeam FastSCP or CrossFTP Server, which might be similar to SourceUSB.