Disguised executable files in spear-phishing emails: Detecting the point of entry in advanced persistent threat

Advanced Persistent Threat (APT) is one of the most serious types of cyber attacks, which is a new and more complex version of multi-step attack. Within the APT life cycle, the most common technique used to get the point of entry is spear-phishing emails which may contain disguised executable files. This paper presents the disguised executable file detection (DeFD) module, which aims at detecting disguised exe files transferred over the connections. The detection is based on a comparison between the MIME type of the transferred file and the file name extension. This module was experimentally evaluated and the results show successful detection of disguised executable files. Keywords—Cyber attacks, advanced persistent threat, spear-phishing emails, disguised executable file, malware, intrusion detection system.