The Role of Firewalls in Network Security : A Prestudy for Firewall Threat Modeling

Sammanfattning: Firewalls help protect computer networks from intrusions and malware by enforcing restrictions on what network traffic is allowed to pass through the firewall into the network. This thesis explores the role of firewalls in network security, with the ultimate goal of advancing attempts to create a threat model for firewalls. Five areas are explored, namely: Definitions of Concepts Firewalls vs. Services as Targets for Direct Attack The Past and Future of Firewalls Approach to Estimating Firewall Security Firewall Configuration and Security Policies These areas are explored using a questionnaire survey. Each question in the questionnaire is either tied to a particular area, or is used to evaluate the respondents’ credibility. The questionnaire has 15 questions, many of which ask for free text answers. The group of potential respondents consists of 209 individuals, of whom about 75 % are authors of scientific articles that discuss firewalls, penetration testing, and other relevant topics. The rest are information security professionals, journalists or bloggers of varying merit that were found online. 20 responses to the questionnaire were received. Responses to qualitative questions were codified to produce some quantitative data. The conclusions drawn based on the results include, among other things: Attackers tend to directly target network services rather than firewalls. Respondents disagreed on whether the role of firewalls is currently changing. A possible approach to estimating firewall security takes into account the network services that the firewall protects. Firewall configurations frequently do not match the security policies of the organizations in which the firewalls are deployed.