Fraud detection apparatus, fraud detection method, and fraud detection program

A fraud detection method including:

• referring to a target function list showing functions to be analyzed and analyzing a supplied program to extract a target function to be analyzed;
• analyzing the program to extract an execution path and a conditional branch;
• referring to a score list showing the probability of meeting the condition of a conditional branch and assigning a score to each of the extracted conditional branches to create a conditional branch score table;
• calculating the probability of reaching the target function to be analyzed from the scores for conditional branches included in the execution path on the basis of the conditional branch score table;
• and
• reporting an execution path having a low reachability probability as a path with a high probability of being a backdoor execution path.

A non-transitory computer readable medium storing a program causing a computer to execute:

• a process of referring to a target function list showing functions to be analyzed and analyzing a supplied program to extract a target function to be analyzed;
• a process of analyzing the program to extract an execution path and a conditional branch;
• a process of referring to a score list showing the probability of meeting the condition of a conditional branch and assigning a score to each of the extracted conditional branches to create a conditional branch score table;
• a process of calculating the probability of reaching the target function to be analyzed from the scores for conditional branches included in the execution path on the basis of the conditional branch score table;
• and
• a process of reporting an execution path having a low reachability probability as a path with a high probability of being a backdoor execution path.