Monero was attacked by 51%: A technical verification of 300 million to take over 6 billion?

Written by AIMan@黄金财经

Did Qubic successfully launch a 51% attack on Monero?

As early as the end of July, rumors circulated within the Monero community that the QUBIC mining pool was conducting an attack on Monero. Now, QUBIC appears to have succeeded.

On August 12, 2025, SlowMist tweeted that the Monero (XMR) network was suspected of undergoing a 51% attack. Monero recently experienced a chain reorganization six blocks deep, mined by an unknown mining pool. However, no mining pool on miningpoolstats holds more than 50% of the hashrate, suggesting this could be a covert malicious attack or an unexpected mining race.

At the time of the QUBIC attack at the end of July, Monero's market capitalization was approximately $6 billion. As of now, XMR's market capitalization is approximately $4.6 billion, a drop of over 20%. Meanwhile, QUBIC's market capitalization is only approximately $2.3 billion. If QUBIC truly succeeds in controlling 51% of Monero's hashrate, we will witness a historic moment: a blockchain with a market capitalization of less than $300 million will take over a blockchain with a market capitalization of $6 billion. What exactly happened? X user OrangeFren posted that Monero experienced a reorganization six blocks deep. The 51% attack appears to have been successful. If you are receiving XMR, please wait at least 10 blocks. Ledger CTO Charles Guilemet stated: Monero appears to be undergoing a successful 51% attack. This privacy-focused blockchain, launched in 2014, has long been a target of attacks by governments and three-letter agencies (note: the FBI) and is currently banned from most major centralized exchanges. The Qubic mining pool has been accumulating hashing power for months and now controls the majority of the Monero network's hashing power. This morning, a major blockchain reorganization was detected. With its current dominance, Qubic can rewrite the blockchain, enabling double spends and censoring any transaction. It is estimated that the cost of sustaining this attack is as high as $75 million per day. While potentially lucrative, it could potentially destroy confidence in the Monero network overnight. Other miners have no incentive to continue the attack, as Qubic can easily orphan any competing blocks, becoming the sole miner. In effect, a blockchain with a market capitalization of $300 million is taking over a blockchain with a market capitalization of $6 billion. Monero's recovery options are limited, and a complete takeover is now possible, even likely. Caffeinated User stated: Qubic just reached 51% of Monero's hashrate. This is a monumental feat. They will become the first to manipulate a cryptocurrency through a 51% attack. They intend to isolate all blocks from all other miners, making themselves the sole mining entity for Monero. The only way to mine Monero is through them, and their profits are three times greater than mining Monero directly. They distribute half of their profits to miners and sell the other half to buy Qubic, which they then send to a burn wallet. If they mine 100% of Monero blocks, they can mine 432 Monero coins per day. At the current Monero price, this is equivalent to $118,342.08. They keep 50% and distribute the rest to miners, earning $59,171.04 per day from Qubic burns. This translates to $414,197.28 burned per week and $1.656 million burned per month. This is insane. This is a historic moment. Qubic, with a market capitalization of less than $300 million, will become the sole miner of a currency with a market capitalization of $6 billion. Qubic founder Come-from-Beyond stated on social media: "It appears that Qubic has achieved a 51% win, surpassing Monero. We are awaiting confirmation from independent institutions." Meanwhile, the Monero team is finalizing the details of its 51% attack protection. Many people have accused us of receiving funding from three-letter institutions to attack this privacy coin. After helping Monero prepare for future battles against these institutions, what are your thoughts now? Of course, some disagree. X user Luke Parker stated that six reorganizations do not mean a successful "51% attack." In this scenario, we would see other mining pools perform infinite-depth reorganizations or mine no blocks (assuming an adversary censors other pools like this one). This does mean that the adversary with a high hashrate is lucky.

Is the Qubic attack on Monero just a demonstration of technology and attention?

Let's first understand Qubic. Qubic was created by Come-from-Beyond, co-founder of the directed acyclic graph (DAG) blockchain IOTA. Qubic is a unique L1 public chain whose core mechanisms are useful proof-of-work (uPoW) and AIGarth. While the computational workload of traditional mining typically boils down to solving arbitrary puzzles, Qubic transforms computing power into actual productivity—training its AI model, called AIGarth. Here's how it works: miners contribute their raw computing resources to Qubic's validators (called Computors). These Computors then use this computing power to train AIGarth directly in their memory, with all operations performed on-chain. Qubic's broader vision is to provide outsourced computing for the real world, inviting third parties such as businesses, universities, hospitals, and research labs to use AIGarth. Through customized smart contracts, these entities can connect, adapt models to their needs, and even train specialized versions using Qubic's computing network. This is like opening a decentralized supercomputer to the world, allowing collaborators to contribute and benefit without compromising security. However, this vision is not yet fully realized. Key components, such as Oracle Machines for seamless data integration, are still under development. To demonstrate the feasibility of outsourced computing in a real-world setting, Qubic has come up with custom mining: Qubic provides computing power outside its network, redirecting some of its computing power to external tasks, such as mining Monero or other PoW currencies. Qubic also states that the true potential of outsourced computing goes far beyond cryptocurrency mining. So, at the end of July, Qubic began custom mining for Monero. Why start with Monero? Qubic officials stated that by entering the high-risk, highly competitive field of proof-of-work (PoW) crypto mining, they not only validated their technology but also attracted industry attention. And what were the results? According to a Qubic blog post, before integrating custom Monero mining, CPUs accounted for only 10% of Qubic's mining power. Due to the allure of higher profitability, as more CPU miners joined the network, this figure has since jumped to around 50%. During the week of July 30th to August 7th, the Qubic network's peak hashrate reached 2.77 GH/s, representing 50% of Monero's global hashrate. A total of 4,285 Monero blocks were discovered, and approximately 517 XMR and 6M XTM were mined. This XMR, approximately $141,658 USD, was sold, with 50% used for Qubic coin buybacks and burns and 50% used to increase miner incentives for additional CPU hashrate. Qubic officials stated that Qubic's profitability for miners is approximately three times that of Monero, prompting a surge in CPU miners to join the Qubic network. During this period, the Monero community launched a DDoS attack against Qubic, but the effect was insignificant. Qubic founder Come from Beyong stated on August 3rd that despite the severe DDoS attack, Qubic still managed to mine 20% of Monero blocks... On August 6th, Qubic lead developer dkat noted on Discord: "I asked for a quote yesterday. It's about $500 per IP, 100Gbps, for 24 hours, including SYN floods and reflection attacks. So it's about $20,000 per day, targeting all Qubic nodes and the ecosystem. They've been DDoSing us for seven consecutive days, so it's about $140,000... What will happen to Monero in the future? Based on various sources, the Qubic network may indeed control over 51% of Monero's hash rate."

This 51% attack, as Qubic officials stated, is intended to verify the technology and attract industry attention.

According to Qubic's official promise, Qubic will "start with a pure 51% domination attempt and then move to 'selfish mining' that only requires 33-40% of the computing power." The founder of Qubic also hinted that it will help Monero fight against the government in the future.

But for Monero, how can the crypto community rebuild its trust in it?

Is Qubic an enemy or a new ally?

It is worth continuing to observe.