Answer
Installation media for ArcGIS Server for Solaris and Linux includes a program called pwdump6.exe, a program that uses Windows API calls that are sometimes associated with viruses. pwdump6.exe allows Windows user accounts to be used with ArcGIS Server on Linux and Solaris.
This program exports Windows users and hashes of their passwords and allows them be imported to ArcGIS Server on Solaris and Linux. Using this component is optional.
It is not called by any component of ArcGIS Server and is not installed on any machine. For it to be used, it must be manually copied off the installation media to a Windows machine and then manually run for the accounts to be migrated.