In the era of the Internet, information security issues are of paramount importance. Software packages invariably have security vulnerabilities. If exploited by malicious hackers, vulnerabilities can cause substantial losses to software corporations and end users. Due to the increase in Advanced Persistent Threat (APT) attacks, vulnerabilities have to be discovered as rapidly as possible. This research focuses on Microsoft Office Word software and proposes the fuzzing vulnerability digging model. In the field of fuzz testing, the traditional approaches consume considerable time and system resources without analyzing file formats. Therefore, the fuzzing vulnerability digging model proposed in this research examines the file format to identify any possible weaknesses. According to the experiments, our proposed model outperforms two benchmarking models, i.e. the FileFuzz tester and MiniFuzz tester, for a fixed period of time. Finally, we present an example which imitates a Shellcode attack carried out via the weaknesses discovered by the proposed model. According to the comparison results, the proposed model has the potential to identify weaknesses in MS Office Word software more effectively and efficiently.