[en] In 1990s, industry demanded the interconnection of corporate and production networks. Thus, Industrial Control Systems (ICSs) evolved from 1970s proprietary and close hardware and software to nowadays Commercial Off-The-Shelf (COTS) devices. Although this transformation carries several advantages, such as simplicity and cost-efficiency, the use of COTS hardware and software implies multiple Information Technology vulnerabilities. Specially tailored worms like Stuxnet, Duqu, Night Dragon or Flame showed their potential to damage and get information about ICSs. Anomaly Detection Systems (ADSs), are considered suitable security mechanisms for ICSs due to the repetitiveness and static architecture of industrial processes. ADSs base their operation in behavioral models that require attack-free training data or an extensive description of the process for their creation. This thesis work proposes a new approach to analyze binary industrial protocols payloads and automatically generate behavioral models synthesized in rules. In the same way, through this work we develop a method to generate realistic network traffic in laboratory conditions without the need for a real ICS installation. This contribution establishes the basis of future ADS as well as it could support experimentation through the recreation of realistic traffic in simulated environments. Furthermore, a new approach to correct delay and jitter issues is proposed. This proposal improves the quality of time-based ADSs by reducing the false positive rate. We experimentally validate the proposed approaches with several statistical methods, ADSs quality measures and comparing the results with traffic taken from a real installation. We show that a payload-based ADS is possible without needing to understand the payload data, that the generation of realistic network traffic in laboratory conditions is feasible and that delay and jitter correction improves the quality of behavioral models. As a conclusion, the presented approaches provide both, an ADS able to work with private industrial protocols, together with a method to create behavioral models for open ICS protocols which does not requite training data.

[eu] 90. hamarkadan industriak sare korporatibo eta industrialen arteko konexioa eskatu zuen. Horrela, Kontrol Sistema Industrialak (KSI) 70. hamarkadako hardware eta software jabedun eta itxitik gaur eguneko gailu estandarretara egin zuten salto. Eraldaketa honek hainbat onura ekarri baditu ere, era berean gailu estandarren erabilerak hainbat Informazio Teknologietako (IT) zaurkortasun ekarri ditu. Espezialki diseinatutako zizareek, Stuxnet, Duque, Night Dragon eta Flame esaterako, ondorio latzak gauzatu eta informazioa lapurtzean beraien potentzia erakutsi dute. Anomalia Detekzio Sistemak (ADS) KSI-etako segurtasun mekanismo egoki bezala kontsideraturik daude, azken hauen errepikakortasun eta arkitektura estatikoa dela eta. ADS-ak erasorik gabeko datu garbietan ikasitako edo prozesuen deskripzio sakona behar duten jarrera modeloetan oinarritzen dira. Tesi honek protokolo industrial binarioak aztertu eta automatikoki jarrera modeloak sortu eta erregeletan sintetizatzen dituen ikuspegia proposatzen du. Era berean lan honen bidez laborategi kondizioetan sare trafiko errealista sortzeko metodo bat aurkezten da, KSI-rik behar ez duena. Ekarpen honek etorkizuneko ADS baten oinarriak finkatzen ditu, baita esperimentazioa bultzatu ere simulazio inguruneetan sare trafiko errealista sortuz. Gainera, atzerapen eta sortasun arazoak hobetzen dituen ekarpen berri bat egiten da. Ekarpen honek denboran oinarritutako ADS-en kalitatea hobetzen du, positibo faltsuen ratioa jaitsiz. Esperimentazio bidez ekarpen ezberdinak balioztatu dira, hainbat metodo estatistiko, ADS-en kalitate neurri eta trafiko erreal eta simulatuak alderatuz. Datu erabilgarriak ulertzeko beharrik gabeko ADS-ak posible direla demostratu dugu, trafiko errealista laborategi kondizioetan sortzea posible dela eta atzerapen eta sortasunaren zuzenketak jarrera modeloen kalitatea hobetzen dutela. Ondorio bezala, protokolo industrial pribatuekin lan egiteko ADS bat eta jarrera modeloa sortzeko entrenamendu daturik behar ez duen eta KSI-en protokolo irekiekin lan egiteko gai den metodoa aurkeztu dira.