The only true fix is upgrading. If you are on a version prior to 6.42.0, upgrade immediately.
This is the most critical best practice. Winbox is a management tool; it should never be accessible from the public internet. mikrotik routeros authentication bypass vulnerability
Run this firewall rule to block external access to Winbox: The only true fix is upgrading
/ip firewall filter
add chain=input protocol=tcp dst-port=8291 src-address=!192.168.88.0/24 action=drop comment="Block Winbox from WAN"
(Adjust the src-address to match your trusted LAN subnet). (Adjust the src-address to match your trusted LAN subnet)
/ip firewall filter
add chain=input protocol=tcp dst-port=8291 action=drop comment="Block WinBox from WAN"
add chain=input in-interface-list=WAN protocol=tcp dst-port=80,443,22 action=drop
add chain=input src-address-list=blocked action=drop
/ip service
set winbox disabled=yes
set www disabled=yes
set www-ssl address=192.168.88.0/24
set ssh address=192.168.88.0/24
/user print
Look for unexpected users, especially those with group=full and no comment.
data = read_file("192.168.88.1", "/flash/rw/store/user.dat") print(data)
Note: Real exploits require handling fragmentation (multiple packets) for files >4KB.