From a member:
"Has anyone found a way to change the ONVIF username and password for the Dahua cameras? After testing with HD Witness, it appears that admin:admin is the ONVIF password and does not relate to the build in accounts which are admin, 888888, and 666666.
I also found through searching that Dahua has a back door telnet login. I'm not sure what all the commands are, but reset reboots the camera. Those credentials are root:vizxv. This was tested on the mini dome and on the small bullet camera."