BISCAL: Bit Vector Based Spatial Calculus for Analyzing the Mis-configurations in Firewall Policies

摘要

Packet filtering in firewalls operates at the network level of the OSI model, or the IP layer of TCP/IP. In a packet filtering each packet is compared to a set of conditions before it is forwarded. Depending on the header of the packet, the firewall accepts or denies the packet. Since business needs are dynamic, firewall policies are constantly being changed and modified. Firewall administration teams in large organizations often process dozens of filter additions and changes daily. This continuous flux causes the firewall configuration to grow dramatically over time. A huge and, subsequently complex, firewall configuration is hard to manage and may require lengthy research in order to add or change a filter and results in mis-configurations in firewall policies. Powerful error classification method was proposed based upon the geometrical interpretation of policies in order to detect such mis-configurations in firewall policies. However, as the filters and key fields of the header increase, it demands high memory and computation time. We propose a topological approach called BISCAL (Bit-vector based spatial calculus) to detect the conflicts in the firewall policles to solve this problem.