## 1 Introduction  
Blockchain technology can potentially revolutionize various industries, including finance, healthcare, and supply chain management [1, 2]. Its decentralized nature offers several advantages over traditional centralized systems, such as increased transparency, immutability, and security. These features have fueled significant adoption of and investment in blockchain technologies. According to Deloitte's 2021 Global Blockchain Survey, 76% of respondents reported that their organizations had adopted blockchain as a digital asset, while 83% believed digital assets would replace fiat currency within the next decade [3]. The growth trajectory of blockchain technology is also evident from projections by Grand View Research Inc., which estimated that the global blockchain technology market would reach USD 1431.54 billion by 2030, with a compound annual growth rate (CAGR) of 87.7%between 2023 and 2030 [4]. Similarly, another report predicted that the blockchain distributed ledger market would grow from USD 2.89 billion in 2020 to USD 137.29 billion by 2027, with a CAGR of 62.7% [5]. While the financial services sector currently dominates the blockchain market, the technology's applications have rapidly expanded into various domains. Beyond cryptocurrencies, blockchain enables cross-border money transfers [6], supports Ethereum Virtual Machine (EVM)-based smart contracts [7], integrates into the Internet of Things (IoT) ecosystem [8; 9], enhances data and identity security [10; 11], and facilitates electronic healthcare records (EHRs) [12; 13; 14]. Additionally, blockchain has been applied to automated logistics systems [15] and the burgeoning market of non-fungible tokens (NFTs) [16]. Despite its transformative potential, blockchain technology faces significant challenges, particularly in security. The decentralized nature of blockchain networks does not render them immune to attacks; on the contrary, it introduces novel vulnerabilities. Blockchain system hacks have increased, and NIST reported a notable rise in vulnerabilities in their published report in 2023 [17], while SonicWall highlighted a sharp rise in cybercrimes in its 2024 Cyber Threat Report [18]. Real-world incidents illustrate the severity of these threats. For example, Ethereum Classic suffered multiple 51% and double-spending attacks in 2019 and 2020, resulting in a loss of over USD 6.7 million [19; 20]. On 10 August 2021, the Poly Network was exploited via a smart contract vulnerability, leading to the theft of USD 611 million--the largest crypto-related hack to date [21]. Similarly, Binance, the world's largest cryptocurrency exchange, faced a major breach in October 2022, with hackers stealing 2 million BNB tokens worth USD 570 million [22; 23]. These incidents underscore the urgency of addressing security challenges within blockchain ecosystems. As blockchain adoption accelerates, understanding its vulnerabilities and implementing robust countermeasures is critical. The current study aims to contribute to this effort by conducting a comprehensive analysis of blockchain attacks, vulnerabilities, and mitigation strategies. A thorough examination of existing security challenges and their impacts can help practitioners and researchers design more resilient blockchain systems. To guide this research, we formulated the following research questions:  
* RQ1: What are the most common types of attacks on blockchain technology, and how do they affect the security and integrity of the system? * RQ2: What security measures and technologies have been employed to detect and mitigate malicious blockchain attacks? * RQ3: How can context-specific mitigation strategies be designed to address the unique requirements and constraints of different blockchain applications? To address these questions, this study adopts a qualitative and quantitative approach to reviewing the state-of-the-art research on blockchain security and privacy.