Inclusion of undocumented features vulnerability accessible when logged on with a privileged access level on the following Schweitzer Engineering Laboratories relays could allow the relay to behave unpredictably: SEL-700BT Motor Bus Transfer Relay, SEL-700G Generator Protection Relay, SEL-710-5 Motor Protection Relay, SEL-751 Feeder Protection Relay, SEL-787-2/-3/-4 Transformer Protection Relay, SEL-787Z High-Impedance Differential Relay
. See product instruction manual appendix A dated 20240308 for more details regarding the SEL-751 Feeder Protection Relay. For more information for the other affected products, see their instruction manuals dated 20240329.
The device includes chicken bits or undocumented features that can create entry points for unauthorized actors.
A common design practice is to use undocumented bits on a device that can be used to disable certain functional security features. These bits are commonly referred to as “chicken bits”. They can facilitate quick identification and isolation of faulty components, features that negatively affect performance, or features that do not provide the required controllability for debug and test. Another way to achieve this is through implementation of undocumented features. An attacker might exploit these interfaces for unauthorized access.