The Open Smart Grid Protocol (OSGP) is currently deployed in various European countries in large-scale Smart Metering projects. The protocol was developed by the OSGP Alliance and published as a standard by the European Telecommunications Standards Institute (ETSI).
We identify several security issues in the OSG Protocol, primarily the use of a weak digest function and the way the protocol utilizes the RC4 algorithm for encryption. A straight-forward oracle attack triggers the leakage of key material of the digest function. We outline how an attacker can make use of the simple protocol structure to send maliciously altered messages with valid authentication tags to the meters.
The results of our analysis have been made available to the manufacturer the beginning of 2014, and mitigation strategies have been discussed with the vendor and utilities.