ICT is becoming a fundamental and pervasive component of critical infrastructures (CIs). Despite the advantages that it brings about, ICT also exposes CIs to a number of security attacks that can severely compromise human safety, service availability and business interests. Although it is vital to ensure an adequate level of security, it is practically infeasible to counteract all possible attacks to the maximum extent. Thus, it is important to understand attacks’ impact and rank attacks according to their severity. We propose SEA++, a tool for simulative evaluation of attack impact based on the INET framework and the OMNeT++ platform. Rather than actually executing attacks, SEA++ reproduces their effects and allows to quantitatively evaluate their impact. The user describes attacks through a high-level description language and simulates their effects without any modification to the simulation platform. We show SEA++ capabilities referring to different attacks carried out against...