Min-Hao Wu

This manuscript introduces MPSD (Malicious PowerShell Script Detector), an advanced tool to protect Windows systems from malicious PowerShell commands and scripts commonly used in fileless malware attacks. These scripts are often hidden in Office document macros or downloaded remotely via PowerShell, posing significant threats to corporate networks. A 2018 report revealed that 77% of successful cyberattacks involved fileless malware, with PowerShell being the primary attack method, as highlighted in Red Canary’s 2022 report. To counter these threats, MPSD leverages the Antimalware Scan Interface (AMSI) to intercept and analyze real-time PowerShell scripts, preventing their execution. It further utilizes VirusTotal to filter out malicious scripts. Unlike traditional methods that rely on direct access to scripts, MPSD detects them before execution, addressing the challenge of hidden or obfuscated scripts. Experimental results show that MPSD outperforms well-known antivirus engines, with a low false-negative rate of 1.83%. MPSD is highly effective against evasion techniques like concatenation, encoding, and reordering, making it a robust tool in the cybersecurity landscape.

In the late 20th century, computer viruses emerged as powerful malware that resides permanently in target hosts. For a virus to function, it must load into memory from persistent storage, such as a file on a hard drive. Due to the significant destructive potential of viruses, numerous defense measures have been developed to protect computer systems. Among these, antivirus software is one of the most recognized and widely used. Typically, antivirus solutions rely on static analysis (signature-based) technologies to detect infections in files stored on permanent storage devices, such as hard drives or USB (Universal Serial Bus) flash drives. However, a new breed of malware, fileless malware, has been designed to evade detection and enhance durability. Fileless malware resides solely in the memory of the target hosts, circumventing traditional antivirus software, which cannot access or analyze processes executed directly from memory. This study proposes the Check-on-Execution (CoE) kernel-based approach to detect fileless malware on Linux systems. CoE intervenes by suspending code execution before a program executes code from a process’s writable and executable memory area. To prevent the execution of fileless malware, CoE extracts the code from memory, packages it with an ELF (Executable and Linkable Format) header to create an ELF file, and uses VirusTotal for analysis. Experimental results demonstrate that CoE significantly enhances a Linux system’s ability to defend against fileless malware. Additionally, CoE effectively protects against shell code injection attacks, including buffer and memory overflows, and can handle packed malware. However, it is important to note that this study focuses exclusively on fileless malware, and further research is needed to address other types of malware.

The number of Internet of Things (IoT) devices has increased dramatically in recent years, and Bluetooth technology is critical for communication between IoT devices. It is possible to protect electronic communications, the Internet of Things (IoT), and big data from malware and data theft with BlueZ’s Bluetooth File Transfer Filter (BTF). It can use a configurable filter to block unauthorized Bluetooth file transfers. The BTF is available for various Linux distributions and can protect many Bluetooth-enabled devices, including smartphones, tablets, laptops, and the Internet of Things. However, the increased number and density of Bluetooth devices have also created a serious problem—the Bluetooth worm. It poses a severe threat to the security of Bluetooth devices. In this paper, we propose a Bluetooth OBEX Proxy (BOP) to filter malicious files transferred to devices via the OBEX system service in BlueZ. The method described in this article prevents illegal Bluetooth file transfers, defending big data, the Internet of Things (IoT), and electronic communications from malware and data theft. It also protects numerous Bluetooth devices, including smartphones, tablets, laptops, and the Internet of Things, with many Linux distributions. Overall, the detection findings were entirely accurate, with zero false positives and 2.29% misses.

The first appearance of viruses can date back to the late last century. As an effective form of malware, viruses reside in the permanent storage of target hosts. Before a virus can execute, that must load into memory from the persistent storage included in the associated file. Due to the reliable destructive power of viruses, many mechanisms have been developed to defend computer systems against these hazardous threats. Antivirus software is one of the most famous and popular among these mechanisms. Most antivirus software uses static analysis (signature-based) technology on files stored in permanent storage, such as hard disks or USB flashes, to detect viruses hidden in files. Fileless malware was developed to enhance the survivability of malware by circumventing detection. Fileless malware only exists in the target hosts’ memory, not files. Antivirus software cannot even access the fileless malware code, much less analyze it, since it may be performed in memory directly without needing to load it from a disk. As a result, it is difficult for an antivirus engine to defend a system against fileless malware attacks. This paper proposes a kernel-based solution called Check-on-Execution (CoE) to detect fileless malware on a Linux system. When a program is going to execute a piece of code in a writable and executable memory area of a process, CoE suspends the code execution first. Coe retrieves the code from memory, packs the code with an ELF header to create an ELF file, and uses VirusTotal to check the file to prevent a Linux system from executing fileless malware. Experimental results show that CoE noticeably enhances the ability of a Linux system to defend itself again fileless malware. CoE is also suitable for protecting a system from shell code injection attacks, such as buffer and heap overflow attacks. It is capable of handling even packed malware. But in this paper, we only focus on fileless malware.

Coinhive released its browser-based cryptocurrency mining code in September 2017, and vicious web page writers, called vicious miners hereafter, began to embed mining JavaScript code into their web pages, called mining pages hereafter. As a result, browser users surfing these web pages will benefit mine cryptocurrencies unwittingly for the vicious miners using the CPU resources of their devices. The above activity, called Cryptojacking, has become one of the most common threats to web browser users. As mining pages influence the execution efficiency of regular programs and increase the electricity bills of victims, security specialists start to provide methods to block mining pages. Nowadays, using a blocklist to filter out mining scripts is the most common solution to this problem. However, when the number of new mining pages increases quickly, and vicious miners apply obfuscation and encryption to bypass detection, the detection accuracy of blacklist-based or feature-based solutions decreases significantly. This paper proposes a solution, called MinerGuard, to detect mining pages. MinerGuard was designed based on the observation that mining JavaScript code consumes a lot of CPU resources because it needs to execute plenty of computation. MinerGuard does not need to update data used for detection frequently. On the contrary, blacklist-based or feature-based solutions must update their blocklists frequently. Experimental results show that MinerGuard is more accurate than blacklist-based or feature-based solutions in mining page detection. MinerGuard’s detection rate for mining pages is 96%, but MinerBlock, a blacklist-based solution, is 42.85%. Moreover, MinerGuard can detect 0-day mining pages and scripts, but the blacklist-based and feature-based solutions cannot.

The bothersome evil twin problem has an active user-side remedy in the form of the Wireless Packet Forwarding Detector (WPFD). The evil twin issue can lead to further security problems, including man-in-the-middle (MITM) attacks. Open public Wi-Fi connections have provided potential answers to this issue, although they often need more data that people either cannot get or are too pricey for regular users. The solution that we created does not require these standards. It allows users’ notebooks to be used to check for evil twins. We have succeeded in developing a user-side detection system that can successfully identify the presence of an evil twin. The packet forwarding behavior generated by the evil twin and the TCP/IP (Transmission Control Protocol/Internet Protocol) protocol are both used by the WPFD. It can identify evil twins without a hitch when we utilize accessible Wi-Fi settings in public spaces or IoT smart homes with unencrypted WLANs (Wireless Local Area Network). However, neither additional data nor a wireless network administrator’s assistance is needed. We compare our work to various publications on popular Rogue Access Points (APs) or IoT (Internet of Things) smart homes. The WPFD does not require any extra setup to install on the host of any end user. According to experimental findings, the WPFD true positive and true negative rates are 100% even when Received Signal Strength Index (RSSI) is 45%.

Various services through smartphones or personal computers have become common nowadays. Accordingly, embedded malware is rapidly increasing. The malware is infiltrated by using short message service (SMS), wireless networks, and random calling and makes smartphones bots in botnets. Therefore, in a system without an appropriate deterrent, smartphones are infiltrated easily. In the security threats by malware, random calling has become serious nowadays. To develop the defensive system against random calling and prevent the infiltration of the malware through random calling, it is required to understand the exact process of how to make bots in the botnet. Thus, this research develops a simple and ingenious mobile botnet covert network based on adjustable ID units (SIMBAIDU) to investigate how a botnet network is established by using phone numbers. Perfect octave coding (P8 coding) turns out to be effective in infiltrating smartphones and executing commands, which is used for botnets. The results provide the basic process of P8 coding which is useful for developing defensive systems of smartphones.

Nowadays, antivirus is one of the most popular tools used to protect computer systems. Diverse antivirus vendors are established to protect their customers against malware. However, antivirus is facing some critical problems, such as significant detection windows, vulnerability inside antivirus, and long scanning time. In this paper, we recommend a cloud-based real-time defense mechanism named Skywalker to allow users to safely utilize antivirus without the above problems. After Skywalker is installed in a host, the host does not need to install any antivirus. However, Skywalker guarantees that the host only executes programs that have been verified by a cloud-based scanner, such as VirusTotal. VirusTotal uses 56 antivirus engines to check whether a program is malware. Research shows that the more antivirus engines are used, the more accurate the result is. Because the above scan is performed right before the execution of every program, Skywalker provides 24/7 real-time protection to a system. Besides, Skywalker eliminates the need to spend a lot of time scanning all files in a host. Experimental results show that after a program has been executed once, it takes Skywalker, at most, 0.47091 s to start the program again. Meanwhile, VirusTotal provides a secure protection to client hosts.