# Understanding and Classifying Permanent Denial-of-Service Attacks
## 2 Background  
Permanent denial-of-service (PDoS) attacks, characterized by their potential to cause long-term or irreversible damage to systems, represent a critical cybersecurity challenge. Distinct from temporary denial of service (DoS) attacks, employing a wide array of sophisticated strategies, PDoS attacks target both software and hardware. These strategies extend beyond mere disruption, aiming to permanently disable the process. Modern PDoS adversaries often employ subtle, long-term tactics to bypass traditional intrusion detection systems, including IP spoofing and mimicking legitimate traffic. They range from distributing malware that corrupts firmware, boot processes, or data to direct hardware manipulations, such as voltage/current alterations. More advanced evasion methods, as seen with malware like Gapz [3], compromise the OS at the kernel level, making detection even more challenging. The intersection of software vulnerabilities and hardware threats has always been a significant concern in the realm of cybersecurity. The first reports of PDoS being successful appeared in public sources about three decades ago but PDoS attacks remain rare due to various reasons, which are discussed later. The known noteworthy occasions where software-induced actions have resulted in tangible hardware damage include the following:  
* Commodore PET's \"Killer Poke\" (Late 1970s): In the early days of personal computing, certain memory interaction commands on the Commodore PET, particularly PEEK and POKE, were rumored to damage the system's hardware. * GPU Stress-Test Applications: Tools, such as FurMark, underscored the potential of software to exert physical stress on hardware, particularly GPUs. When misused, they can lead to overheating. * Overclocking and Voltage Manipulation: Theoretical malware could force CPUs or GPUs to operate beyond safe thresholds, though the modern systems typically have mechanisms to counter such threats. * Hoaxes and Mythical Threats: Many purported threats, like the \"Data Crime Virus\" of the 1980s, turned out to be baseless, despite causing initial alarm. While the above are only techniques or even speculations, the following are specific real-world examples of cyber attacks that used unique attack vectors to prevent the functionality of the device:  
* Stuxnet--ICS malware, kinetic impact;
* BrickerBot, NotPetya, PaperW8 [8]--wiper, corruption of storage;
* CVE-2022-23968 [11] --a reported vulnerability in Xerox VersaLink that, when exploited, sends device into a restart loop;
* Siemens ET200S nmap service scan--ICS malware, temporary shutdown of the Programmable Logic Controller. The academic publications addressing PDoS (permanent denial-of-service) cyber attacks directly are limited, and this survey was carried out to address this gap. Thissurvey included academic articles, whitepapers, and technical reports available from open public sources. The most widely used example is the malware BrickerBot [5], which has undergone considerable investigation, most notably in the study by [PERSON] et al. [12]. Their research offers an in-depth analysis of BrickerBot's capabilities, targeting methods, and potential impact. However, this research, as well as most of the analyzed studies, have a focus on a specific area and often lack a comprehensive holistic study of the entire attack type. PaperW8 [8] further studied IoT wiper techniques and presented a new malware. Another gap in the current academic literature is the lack of consistent methodology for studying PDoS attacks. Individual studies are often constrained by their own scope, which may be limited to specific types or categories of attacks, and only mention the possibility of PDoS [13, 14]. Despite these limitations, the existing literature creates a path toward understanding the mechanics of PDoS attacks, such as the methods used for propagating the malware or the intricacies of the attack vectors.