Compastié, MaximeLópez Martínez, AntonioFernández, CarolinaGil Pérez, ManuelTsarsitalidis, StylianosXylouris, GeorgeMlakar, IzidorKourtis, Michail AlexandrosŠafran, Valentino2023-04-202023-04-202023Compastié M, López Martínez A, Fernández C, Gil Pérez M, Tsarsitalidis S, Xylouris G, Mlakar I, Kourtis MA, Šafran V. PALANTIR: an NFV-based security-as-a-service approach for automating threat mitigation. Sensors. 2023;23(3):1658. DOI: 10.3390/s230316581424-8220http://hdl.handle.net/10230/56514Small and medium enterprises are significantly hampered by cyber-threats as they have inherently limited skills and financial capacities to anticipate, prevent, and handle security incidents. The EU-funded PALANTIR project aims at facilitating the outsourcing of the security supervision to external providers to relieve SMEs/MEs from this burden. However, good practices for the operation of SME/ME assets involve avoiding their exposure to external parties, which requires a tightly defined and timely enforced security policy when resources span across the cloud continuum and need interactions. This paper proposes an innovative architecture extending Network Function Virtualisation to externalise and automate threat mitigation and remediation in cloud, edge, and on-premises environments. Our contributions include an ontology for the decision-making process, a Fault-and-Breach-Management-based remediation policy model, a framework conducting remediation actions, and a set of deployment models adapted to the constraints of cloud, edge, and on-premises environment(s). Finally, we also detail an implementation prototype of the framework serving as evaluation material.application/pdfeng© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).info:eu-repo/semantics/articlehttp://dx.doi.org/10.3390/s23031658Security-as-a-Servicesecurity orchestrationpolicy-driven managementvirtual network functionsfinite state machinesconstraints programminginfo:eu-repo/semantics/openAccess