# Network Security Node-Edge Scoring System Using Attack Graph Based on Vulnerability Correlation
## 4 Experiment
### Priority Evaluation According to Attack Route  
First, the attack priority was calculated through a method that suggested the risk of each node and edge. Table 6 lists the result of calculating the risk for each node, and Table 7 presents the result of calculating the risk for each edge. C\({}^{1}\) and C\({}^{2}\) denotes CVE-2007-5969, CVE-2014-2440. All values related to CVSS were calculated based on version 2.0. The node risk was calculated using the CVSS basic score of the vulnerabilities of each node (PC, server, etc. ), and the edge risk was calculated by applying the risk calculation method suggested in Section 3. Regarding the weight of each item of edge risk, the attack location, attack type, and node association were judged to be more important than the CIA, and the weight was calculated while reflecting this. Figure 1: Network that included nodes and vulnerabilities generated in this experiment. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & & \multicolumn{2}{c}{\(v_{i}\)} \\ \cline{3-4}  & & \(v_{i}\)\(\in\)\(v_{I}\) & \(v_{i}\)\(\
otin\)\(v_{I}\) \\ \hline \multirow{2}{*}{\(v_{I}\)} & \(v_{i}\)\(\in\)\(v_{I}\) & 5 & 3 \\ \cline{2-4}  & \(v_{i}\)\(\
otin\)\(v_{I}\) & 3 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Weight according to preconditions between two nodes. For the node risk, the experimental results confirmed that nodes with vulnerabilities with relatively high CVSS scores showed higher values. It was confirmed that nodes with various vulnerabilities scored higher than attacks that could penetrate through a single vulnerability, such as nodes C, G, and I, and that nodes that could attack with various nodes such as nodes D and G also scored higher. In terms of the edge risk, it was confirmed that the nodes (attack locations) that can be accessed from outside rather than inside and the attack types that occurred more frequently as of 2021 showed relatively higher risks. As a result of comparing D-G and G-D edge analysis, it was confirmed that the edge risk differed depending on the correlation between each vulnerability, and that even when connected to various nodes such as node D, different risk scores were calculated depending on how the vulnerability of each node was related to the vulnerability of node D. Further, in the case of A-C, it was confirmed that the vulnerabilities used to attack the two nodes and the corresponding correlation showed different edge risks, although they were the same nodes. Next, the risk for each attack route was calculated based on the calculated node and edge risk; Table 8 lists the attack route used in this experiment. Table 9 lists the results, and the attack route risk was calculated with 10 as the maximum. In the attack pathroute risk calculation, along with the risks of nodes and edges, the path route that was calculated based on the total number of nodes passed to reach the final target, node J, is also included. pathroute is a value obtained by dividing the maximum number of routes to reach the final goal by the number of corresponding attack routes. The longer the pathroute, the lower the value. There were six routes in total, and the nodes and the edges used according to each route were as follows. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Node** & **Node Risk** & **Node** & **Node Risk** \\ \hline A & 0 & F & 2.1 \\ \hline B & 5 & G & 6.25 \\ \hline C1 & 7.1 & H & 4.6 \\ \hline C2 & 5.1 & I & 6.4 \\ \hline D & 7.2 & J & 2.1 \\ \hline E & 2.1 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Node risk calculation results. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Edge** & **Edge Risk** & **Edge** & **Edge Risk** \\ \hline A-B & 2.4664 & D-H & 3.2968 \\ \hline A-C1 & 3.9514 & D-I & 2.1914 \\ \hline A-C2 & 2.7964 & D-G & 2.6864 \\ \hline B-D & 3.6214 & G-D & 7.6214 \\ \hline C-G & 7.7026 & G-I & 2.4114 \\ \hline D-E & 5.9976 & I-J & 1.9164 \\ \hline D-F & 1.9976 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Edge risk calculation results.