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The back door into the control system
One of the enduring beliefs held in the SCADA and control systems world is that control systems are secure because they are simply never connected to the Internet. But if this is the case, then how are all these viruses getting to the plant floor and infecting SCADA systems?
To answer this question, the study team looked more closely at the category of events reporting a remote point of entry. The data set was reduced to the 47 incidents that occurred between 2002 and 2006 and had ‘Remote’ in the point-of-entry field. Figure 5 graphs the frequency distribution of each of the nine remote point-of-entry categories: Internet, corporate WAN, corporate business LAN, wireless system, trusted third party, VPN connection, public telecommunications network, and dial-up modem.
Fig. 5. Remote points of entry charted as a percentage from 2002 to 2006( 47 records)
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