The increasing importance of the Internet as an integral part of contemporary society has stressed the need to formalize the process of response to security incidents that accompany it inseparably. Security teams of the CERT/CSIRT type are established at different levels for this purpose. These teams respond to reports from their constituency and cooperate with other teams. This thesis introduces the reader to the issues these teams deal with and analyzes their needs in resolving threats and problems related to DNS and its domains. Part of the work is an overview of the basic existing tools to support the work of CERT/CSIRT teams to solve problems with domains, the design of a tool Malicious Domain Manager and description of its implementation. The results of test run of this tool by CZ.NIC-CSIRT team show its contribution to security of DNS.

Threat management of water distribution systems is essential for protecting consumers. In a contamination event, different strategies may be implemented to protect public health, including flushing the system through opening hydrants or isolating the contaminant by manipulating valves. To select the most effective options for responding to a contamination threat, the location and loading profile of the source of the contaminant should be considered. These characteristics can be identified by utilizing water quality data from sensors that have been strategically placed in a water distribution system. A simulation-optimization approach is described here to solve the inverse problem of source characterization, by coupling an evolutionary computation-based search with a water distribution system model. The solution of this problem may reveal, however, that a set of non-unique sources exists, where sources with significantly different locations and loading patterns produce similar concentration profiles at sensors. The problem of non-uniqueness should be addressed to prevent the misidentification of a contaminant source and improve response planning. This paper aims to address the problem of non-uniqueness through the use of Niched Co-Evolution Strategies (NCES). NCES is an evolutionary algorithm designed to identify a specified number of alternative solutions that are maximally different in their decision vectors, which are source characteristics for the water distribution problem. NCES is applied to determine the extent of non-uniqueness in source characterization for a virtual city, Mesopolis, with a population of approximately 150,000 residents. Results indicate that NCES successfully identifies non-uniqueness in source characterization and provides alternative sources of contamination. The solutions found by NCES assist in making decisions about response actions. Once alternative sources are identified, each source can be modeled to determine where the vulnerable areas of the system are, indicating the areas where response actions should be implemented.

Current thesis is a documentative approach to sum up experiences of a practical projectof implementing Cyber Threat Intelligence into an existing information securitymanagement system and delivering best practices using action design researchmethodology. The project itself was delivered to a multinational energy provider in 2017.The aim of the CTI-implementation was to improve the information security posture ofthe customer. The author, as participant of the delivery team presents an extensive reviewof the current literature on CTI and puts the need for threat intelligence into context. Theauthor claims that traditional security management is not able to keep up with currentcybersecurity threats which makes a new approach required. The thesis gives an insightof an actually working and continuously developed CTI-service and offers possible bestpractices for InfoSec professionals, adds theoretical knowledge to the body of knowledgeand opens up new research areas for researchers.

Cumulative effects from multiple anthropogenic stressors over the past three centuries have severely impacted estuarine and coastal habitats, with cascading effects on the species that rely upon them. Pacific salmon (Oncorhynchus sp.) are migratory species that use estuaries as juveniles and as adults and deliver critical nutrients to coastal ecosystems as they move between fresh and marine waters. Many once abundant salmon populations have been extirpated or are in severe decline relative to historic levels, yet the strength of the relationship between habitat loss and population productivity has been challenged. In this dissertation, I applied field studies, otolith analyses, and conservation decision science tools to investigate the relative importance of estuarine habitat to salmon populations, with the aim of advancing effective management solutions for these species and their habitats. First, I conducted a two-year field survey of fish communities in the Fraser River estuary, British Columbia, Canada comparing the species richness and relative catch amongst three distinct habitats. I found that this impacted estuary still supported a rich community of migratory marine and anadromous fishes, as well as resident estuarine fish species. Each habitat supported some unique fish assemblages, with eelgrass supporting the highest catch and diversity of fishes overall but brackish marsh supporting the highest and most consistent catch of salmonids. Next, I used otolith analyses to quantify the residency and growth of juvenile Chinook salmon in the estuary. I found that for one of the only two remaining Chinook salmon stocks abundant enough to still support limited harvest in the Fraser River, the estuary provides vital rearing habitat, with juveniles residing in the estuary for an average of 6 weeks, during which time they had mean daily growth rates of 0.57 mm fork length, approximating growth in healthier estuarine systems. The use of these habitats by juvenile Chinook salmon had not been quantified previously, so these findings directly inform management of this population, which was recently designated as Threatened by the Committee on the Status of Endangered Wildlife in Canada. Finally, I applied Priority Threat Management, a conservation decision science framework, to predict the future status of Pacific salmon in the lower Fraser River and identify the most cost-effective conservation solutions out of a suite of alternative management strategies. On our current trajectory none of these populations were predicted to be assessed as ‘green’ or healthy status at the end of 25 years. In contrast, implementation of broad scale habitat restoration, protection, and watershed management could considerably improve the viability of the lower Fraser to support these salmon, such that many (14/19) of these populations would have a >50% likelihood of being assessed as healthy. Together, this research provides novel evidence of active and selective use of estuarine habitats by juvenile salmon, reliance on estuarine habitat for early marine growth by juvenile Chinook salmon, and a direct link between habitat health and population status for lower Fraser River salmon populations. / Graduate / 2023-04-13