Security Strategies in Linux Platforms and Applications, 3rd Edition

Alternate Attack Vectors

While it’s very uncommon today, you may still run across situations where older technologies are used. This could be the case in legacy environments or even in cases where there is operational technology that is not intended to be connected to a traditional information technology (IT) network. You may find serial interfaces, for instance. You may also find old modem technology that also uses a serial-based interface but rather than connecting through hard wires that are fixed, they would use on-demand connections, either inbound or outbound.

Malicious users who break into a local system would have access to these older services. Some services can be run with administrative permissions and should be regulated carefully. ...