Recently my Win 10 network neighborhood started showing a device on the network named OPENWRT. My router is a MiKroTik unit which has been running my network for several years and has not been recently upgraded. The network shows the following shares on the openwrt device:
disk_sataa1, disk_sataa5, disk_sataa6, disk_sataa7,
disk_satab1, disk_satab5, disk_satab6,
Disk_sda1, Disk_sdb1, Disk_sdc1,
If I try to access one of these shares I get a message that windows cannot acces the share.
The most recent change to my network was that the ISP (Spectrum) installed a new modem to handle its VoIP system. That modem is a docsis 3 compliant unit but I am not sure of the manufacturer.
(but we can't really help you with mikrotik issues here)
Some of which are serious enough that an external attacker might have taken over your device. If that's the case, all bets are off (and the attacker might even have replaced the mikrotik firmware with their own, bugged firmware, which might be loosely based on OpenWrt).
That said, your first task would be identifying the new device - be it through the IP/ MAC address or disconnecting all devices one by one, until it disappears.
No. Its IP address matches the device which is a Dune 4K HD Media player. I am just surprised that the Dune media player shows itself by the name openwrt. I believe it used to show itself with another name. I will be looking into the settings on the Dune media player later.
Googling for "Dune 4K HD Media Player OpenWrt" yields several interesting results... looks like that device does have a firmware based on OpenWrt, and some users seem to have found the same issue you mention here.