The attack on Monero in 2025 raised questions about the stability and reliability of decentralized blockchains. This article discusses the key aspects of this incident and its implications.
What is a 51% Attack?
In proof-of-work (PoW) blockchains, miners compete to solve cryptographic puzzles to validate transactions. The security of such networks is based on the assumption that no single entity controls more than 50% of the network's hashrate.
If someone does control that amount, they can:
* Reorganize blocks and reverse transactions, creating double-spends * Exclude or censor other miners' work * Prevent new transactions from being confirmed
While such interference seems impossible, in reality, hashrate can be rented or redirected, making attacks economically accessible.
Monero vs Qubic: When Miners Chose Greed
The attack on Monero in 2025 was not the result of hackers. Qubic offered miners a deal that was hard to resist—tripled mining rewards. As a result, many miners who had supported Monero left the network.
As reported by Rekt News:
*CITE_NA* "Triple rewards proved more powerful than years of ideological commitment to decentralization."
However, the outflow of hashrate led to a temporary imbalance in Monero's network, resembling a classic 51% attack. This severely undermined the reputation of privacy coins.
Lessons from History: Other 51% Attacks
The incident with Monero is not unique. PoW networks with smaller hashrates are vulnerable to similar attacks. Examples include:
* Ethereum Classic (ETC) was hit multiple times in 2019 and 2020. * Horizen faced a major attack in 2018, likely linked to ASIC testing. * Bitcoin Gold and Verge experienced repeated attacks between 2018 and 2020.
Each of these cases reinforced the conclusion: PoW security depends less on ideology and more on economics.
The Monero incident highlights that blockchain systems are protected not only by mathematical algorithms but also social factors. The effectiveness of decentralization often relies on the financial interests of miners, which makes these networks vulnerable to attacks.
