I've seen open a new window with a client telnet sesion at login this morning at SBS 2011 server. The window displayed some random chars (non alphanumerics) a few seconds and gone. The server is fully updated and doesn't have any script at logon. Typical default services are on: Exchange, IIS, etc, but no more. The server is behind a router, and have NAT only on the necessary few ports.
I manage other two Windows 2008 R2 VPS and I've seen this before on these.
Aparently nothing happened to the servers. But I'm worried about this.
What do you recommend me, please?