RB751u hacked , now Cannot upgrade using Netinstall.

Hi everyone,
Im new in the forum. I have been using Mikrotik from various years, in Argentina.

Recently we are infected in some of this routers with Coinhive and Socks-Proxy virus… (winbox port opened freely to internet… yeah! )
We have recovered some ones and applied the security indications recommended (upgrade to latest version and change passwords, and close the winbox and anothers ports).

Actually we have a problem with one RB751U-2HND. I can remove the scripts from the MK. Aparently is 100% clear.
But:

  • I cannot upgrade (or downgrade) the firmware. Currently is 6.37.3, however I have tested with “fsystem routerboard settings set force-backup-booter=no
  • I cannot modify this unit for enter in Netinstall (I change the boot device to “try-ethernet-once-then-nand” but the unit cannot connect in Netinstall, boots normally.
  • In one instance that have used the reset button, have captured this TFTP request (using Wireshark from the PC connected directly to mikrotik)

Update: The image (if is not loading) says “TFTP 70 Read Request, File: vmlinux, Transfer type: octet, blksize=512”

Any ideas?
Thanks in advantage.
Sorry for my english :slight_smile:

BUMP @mikrotikstuff

Thanks !!