Information Centric Networking (ICN) is seen as a promising solution to re-conciliate the Internet usage with its core architecture. However, to be considered as a realistic alternative to IP, ICN must evolve from a pure academic proposition deployed in test environments to an operational solution in which security is assessed from the protocol design to its running implementation. Among ICN solutions, Named Data Networking (NDN), together with its reference implementation NDN Forwarding Daemon (NFD), acts as the most mature proposal but its vulnerability against the Content Poisoning Attack (CPA) is considered as a critical threat that can jeopardize this architecture. So far, existing works in that area have fallen into the pit of coupling a biased and partial phenomenon analysis with a proposed solution, hence lacking a comprehensive understanding of the attack's feasibility and impact in a real network. In this paper, we demonstrate through an experimental measurement campaign that CPA can easily and widely affect NDN. Our contribution is threefold: (1) we propose three realistic attack scenarios relying on both protocol design and implementation weaknesses; (2) we present their implementation and evaluation in a testbed based on the latest NFD version; and (3) we analyze their impact on the different ICN nodes (clients, access and core routers, content provider) composing a realistic topology.