Trailer Power Line Communications

The National Motor Freight Traffic Association (NMFTA) and Assured Information Security (AIS) have released research detailing a vulnerability within trailer Power Line Communications (PLC) signals. Their research indicates it is possible to read PLC signals using active antennas reliably at 6 feet and up to 8 feet away, subject to environmental conditions. The researchers expect to be able to push this reception distance further with receiver improvements. The impact of this issue depends heavily on what information is being sent by ECUs on the trailer PLC bus. Typical trailer traffic is only ABS fault messages and will thus have minimal loss of confidentiality. CISA is publishing this advisory to bring awareness to trailer and brake manufacturers who may be seeking to leverage PLC for sensitive information: e.g., air weigh axles or key exchange in setting up high-speed wireless links in future tractor-trailer interfaces.