The privacy-focused cryptocurrency Monero has experienced a significant disruption, with 60 mined blocks discarded from its blockchain within 24 hours amid an ongoing attempted 51% attack by the Qubic network. According to the Monero Consensus Status dashboard, Monero saw 60 orphaned blocks (valid blocks rejected from the main chain) in the last 720 blocks. This disruption coincides with an ongoing economic attack by the Qubic network, which incentivizes selfish mining. Qubic miners redirect their computing power to mine Monero and sell the proceeds to buy and burn Qubic tokens, while being paid in QUBIC. This setup reportedly allows Qubic miners to earn more than Monero miners. The attack has raised fears of a potential “51% attack” — a rare and serious event that can enable attackers to rewrite or block transactions. An orphaned block is a valid block excluded from the main chain because another competing block at the same height was accepted first. In selfish mining, a miner with significant hashrate withholds blocks and publishes them strategically to overtake the public chain, causing honest miners’ work to be discarded. As of writing, Monero’s price stands at over $247, down more than 8.6% from over $276 reported 24 hours earlier.

Qubic Attack Disrupts Monero Network

Qubic’s Monero mining pool openly engages in selfish mining, with Qubic founder Sergey Ivancheglo admitting it in an X post. Ivancheglo claimed in a Tuesday X post that “Qubic has achieved 51% over Monero” and the team is “waiting for independent confirmations.” A 51% attack occurs when a single entity—in this case, the Qubic mining pool—controls over half of a blockchain network’s mining power or stake, allowing them to manipulate transactions. Zhong Chenming, co-founder of crypto cybersecurity firm SlowMist, said in a Tuesday X post that “this time the 51% attack on Monero seems to have succeeded.” He added:

“The cost was also high, and it’s unclear what the economic benefits of doing this are in the end… In theory, the Qubic mining pool can now rewrite the blockchain, achieve double-spending, and censor any transactions.”

Not Everyone Is Convinced

Doubts remain about whether a successful 51% attack actually occurred. Selfish mining with control over a high percentage of hashrate, but short of a majority, can occasionally lead to orphaned blocks. Monero’s total hashrate, according to CoinWarz, is estimated at 5 GH/s. Unverified data from Qubic claims a peak hashrate of 3.01 GH/s, which would be sufficient, but a current hashrate of 2.08 GH/s, which is insufficient for a 51% attack. The Monero Consensus Status also indicates that blocks mined by unknown mining pools and solo miners—including Qubic—reached nearly 30% on August 11. This could mean Qubic controlled most of the hashrate briefly or a significant minority. SeraiDEX’s lead developer, Luke Parker, noted in an X post that a six-block-deep network reorganization with block orphaning “does not mean a ‘51% attack’ was successful.” He added, “It does mean an adversary with a high amount of hash got lucky.”

Hack War Escalates Between Networks

Qubic and Monero are engaged in an ongoing hack war, exchanging countermeasures. Ivancheglo previously wrote on X that Monero broke Qubic’s selfish mining system, prompting his fix. Earlier, Ivancheglo accused Monero mining software developer Sergei Chernykh of denial-of-service (DDoS) attacks on Qubic’s pool, which Chernykh disputes. The attack began in late July when the community noticed what it described as an “economic attack.” This operation uses economic incentives—paying Qubic miners more than Monero miners—to attempt control over most of Monero’s hashrate and network. Niko Demchuk, head of legal at onchain forensics firm AMLBot, told Cointelegraph that Qubic’s attack on Monero could be considered “computer sabotage” or “unauthorized access” under Belarusian and European Union laws. However, no statute explicitly mentions 51% attacks. Demchuk said Belarus’ cybercrime rules might apply if blockchain manipulation disrupts protected systems.

Source: Cointelegraph — Tue, 12 Aug 2025

Frequently Asked Questions (FAQ)

Understanding the Monero Network Disruption

Q: What happened to the Monero network? A: The Monero network experienced a significant disruption, with 60 mined blocks being orphaned (rejected from the main chain) within a 24-hour period. Q: What is an orphaned block? A: An orphaned block is a valid block that is temporarily mined but ultimately rejected from the main blockchain because another competing block at the same height was accepted first. Q: What caused the block orphaning? A: The block orphaning is believed to be caused by an ongoing attempted 51% attack orchestrated by the Qubic network, utilizing a selfish mining strategy. Q: What is a 51% attack in cryptocurrency? A: A 51% attack occurs when a single entity or group controls more than half of a blockchain network's mining power (hashrate). This control allows them to potentially manipulate transactions, double-spend coins, or censor transactions. Q: What is selfish mining? A: Selfish mining is a strategy where a miner with a substantial amount of hashrate withholds mined blocks and strategically releases them to gain an advantage over the public blockchain, leading to discarded work by honest miners. Q: What is the Qubic network's involvement? A: The Qubic network is reportedly incentivizing its miners to mine Monero and sell the proceeds to buy and burn Qubic tokens, while also being paid in QUBIC. This strategy appears to allow Qubic miners to earn more than Monero miners. Q: Did the 51% attack on Monero succeed? A: While some sources suggest the attack may have succeeded, there are doubts. Selfish mining with a significant, but not majority, hashrate can also lead to block orphaning. The actual extent of Qubic's hashrate control is unverified by some sources. Q: How has this affected Monero's price? A: As of the report, Monero's price had dropped by more than 8.6%, falling to over $247 from over $276 in the preceding 24 hours. Q: Is this a new type of attack? A: The Qubic network's method is described as an "economic attack," using financial incentives to gain control of the network's hashrate. Q: Are there legal implications for this attack? A: Legal experts suggest that Qubic's actions could be considered "computer sabotage" or "unauthorized access" under Belarusian and EU laws, though no specific statutes explicitly cover 51% attacks.

Crypto Market AI's Take

This incident highlights the ongoing challenges in maintaining the integrity of decentralized networks against sophisticated economic attacks. The Monero network's privacy features, while beneficial for users, can also make it more challenging to track and attribute such activities. The strategy employed by Qubic, leveraging its own tokenomics to incentivize Monero mining, is a novel approach to gaining network dominance. Understanding these evolving attack vectors is crucial for the broader cryptocurrency ecosystem. For insights into how AI is being used to enhance security and detect anomalies in blockchain networks, you can explore our resources on AI in Cybersecurity and our analysis of AI-driven trading bots.

Monero price dips as Qubic likely succeeds in 51% attack