The vmss2core tool may be downloaded as a standalone utility in the Free Downloads of Broadcom Support Portal (BSP): Donwload VMware Flings for Free or alternatively bundled with VMware Workstation.
VMware vSphere ESXi
VMware Workstation
The vmss2core tool is distributed separately as well as bundled with VMware Workstation.
To access vmss2core, download that standalone utility in Free Downloads of the Broadcom Support Portal (BSP) or install VMware Workstation. After installation, the tool will be located at:C:\Program Files (x86)\VMware\VMware Workstation\vmss2core.exe
For more details and usage instructions, refer to the official Broadcom Knowledge Base article:
KB 323788 – Using vmss2core