Your experience on drop-outs of PLCs during network scans

[StefanLueders]

Hello !

After observing several drop-outs of some of our PLCs, it turned out, that the corresponding Ethernet communcation modules were blocked after the execution of network scans / port scans (using e.g. "nmap" or "Nessus"). In the most severe cases the blockage could only be fixed by power-cycling the whole PLC.

We started some investigation on the inherent security of PLCs from three different manufacturers and came to the conlusion that manuy of them have no protection at all (e.g. running unprotected WebServers, SMTP, FTP, ...).

Does anybody have made similar experiences ? Do I have to worry on Viruses, Worms, Hackers doing similar things ?

Thanks a lot S>>L

P.S. I intentionally did not mention the PLC types.

 

[OldPfart]

Don't use Ethernet. I won't. I use proprietary token ring type networks. Much more relable and they work.