Bitcoin Satoshi’s Imaginative and prescient, the fork of one other Bitcoin (BTC) fork, has for the third time in three months suffered a blockchain reorganization (reorg) assault. With a name to all stakeholders to mark the malicious community department as invalid, Bitcoin SV (BSV) builders say the assaults have been repelled and all fraudulent chains recognized.

The flurry of assaults towards Bitcoin SV, although reportedly repelled, spotlight the dangers related to proof-of-work (PoW) blockchains which have a low quantity of hash charges backing their existence. Certainly, aside from Bitcoin SV, several chains, like Ethereum Basic (ETC) and Firo — previously often known as Zcoin — have been victims of such attempted blockchain reorg exploits.


Whereas not all of such assaults are profitable, some proceed with vital financial penalties for sincere individuals and the community, usually, because the rogue actors liable for the malicious exploit on the community can double-spend “cash.” The issue has reached the extent that it’s theoretically potential to launch these assaults with just a few thousand {dollars} value of rented hashing energy.

One other blockchain reorg assault

Earlier in August, Bitcoin SV suffered a suspected 51% attack that was much like earlier incidents that occurred between the tip of June and the primary week of July. On the time, it was mentioned that the malicious community exploit resulted in three variations of the primary chain being mined concurrently amid a deep blockchain reorg assault.

Any such assault happens when a malicious actor controls 51% of the community’s hash charge and may use that hashing energy majority to manage and stop block manufacturing in addition to double-spend cash. The Aug. 3 incident is reportedly the largest-scale exploit towards BSV because it forked from Bitcoin Money (BCH) again in 2018.

At one level in the course of the exploit, the attacker reportedly compromised about 10 hours’ value of transactions on the Bitcoin SV chain, in keeping with Nikita Zhavoronkov, lead developer at blockchain explorer Blockchair. Reacting to the occasion, the Bitcoin Affiliation — a Bitcoin SV advocacy group — suggested sincere node operators to mark the false chains initiated by the hacker as invalid.

Marking break up chains initiated by 51% attackers as invalid is important to forestall the hackers from accruing any financial profit, similar to double-spending. Often, the objective of such incidents is to ship mined cash from the pretend chain to the exchanges, thereby extracting financial worth from “skinny air.”

In its incident replace report, the Bitcoin Affiliation stated that the hacker’s tried 51% assaults had been unsuccessful, whereas urging community individuals to make sure that their nodes are solely interacting with the chain supported by sincere miners. As a part of its report, the Bitcoin Affiliation said that every one related stakeholders, together with the Bitcoin SV Infrastructure Crew, will proceed to watch the community to forestall any additional assaults.

In a dialog with Cointelegraph, Steve Shadders, chief know-how officer of Bitcoin SV developer nChain, said that each stakeholders are implementing “a spread of proactive and reactive measures” to forestall additional assaults.

“Along with the Bitcoin Affiliation group, we additionally labored with exchanges, miners and ecosystem companies to rapidly invalidate the fraudulent chain containing the unlawful double-spends by utilizing the invalidateblock command — an RPC code launched to Bitcoin in 2014 and nonetheless a part of the codebase for each BTC and BCH.”

In line with Shadders, this transfer invalidated the attacker’s efforts, permitting sincere individuals to direct their hashing energy to the right chain. Shadders additionally said that the assault had galvanized extra hashing energy to the Bitcoin SV chain to “defend the community.” Certainly, knowledge from BitInfoCharts shows a rise in Bitcoin SV hash charge between Aug. 3 and Aug. 4, with the community’s hashing energy rising by nearly 15%.

Three assaults in as many months

The truth that there have been three assaults in three months, every utilizing related strategies, has introduced up discuss of whether or not there may be an agenda towards Bitcoin SV. Between June 24 and July 9, Bitcoin SV suffered 4 separate tried 51% assaults that resulted in double-spent cash being despatched to Bitmart crypto alternate.

In July, Cointelegraph reported that Bitmark was seeking a restraining order from a New York decide to forestall the hackers liable for the 51% assaults on Bitcoin SV from promoting their double-spent cash. As of this writing, it’s not obvious whether or not the August attacker was capable of ship double-spent BSV to any alternate.

In a observe despatched to Cointelegraph, the Bitcoin Affiliation clarified that the existence of double-spend transactions within the June and July assaults didn’t have any detrimental impact on Bitcoin SV customers, including:

“It’s potential that the malicious actor has been double-spending their very own transactions. No losses have been incurred and no one has had something stolen.”

The June 24 and July 1 assaults reportedly went unnoticed, with investigations beginning solely after the July 6 incident. On the time, some exchanges, together with Huobi, paused deposit and withdrawal providers for BSV, thereby setting off inaccurate speculations that buying and selling platforms had been transferring to delist the coin.

Commenting on the probability of the August assaults being linked with the sooner incidents, Shadders advised Cointelegraph: “At this stage, whereas we wouldn’t have definitive proof that the identical malicious actor is liable for each these newest assaults and the sooner makes an attempt in June and July, the similarity in assault vector and methodology would point out that it’s prone to once more be the identical attacker.”

The one distinction between the 2 units of assaults is that the June and July exploits used the pseudonym “Zulupool” — not linked to the legit Hathor Community miner of the identical title — whereas the August hacker impersonated the Taal mining pool. Certainly, the June and July attacker is believed to have impersonated Zulupool and has additionally been linked to the block reorg exploit towards Bitcoin ABC again in March.

Given the suspected hyperlinks between all of the assaults, Shadders advised Cointelegraph that authorized steps had been being taken, stating:

“Bitcoin Affiliation and its authorized representatives are actively engaged with legislation enforcement in affected jurisdictions — a course of which the Bitcoin SV Infrastructure Crew is supporting on an ongoing foundation by gathering and collating all the forensic proof that the attacker has left behind.”

Weak PoW networks

PoW networks with considerably decrease hash charges are weak to 51% assaults because the required hashing energy required to commandeer the community solely prices just a few thousand {dollars}. In some instances, just a few hundred {dollars} value of rented hashing energy from NiceHash is sufficient to stage a blockchain reorg exploit on some PoW chains.

In line with knowledge from Crypto51 — a platform that tracks the theoretical value of a 51% assault on PoW chains — it costs about $5,200 to hire the hashing energy wanted for a 51% assault on Bitcoin SV for one hour.

Ethereum Basic, one other PoW community, additionally suffered multiple 51% attacks in 2019 and 2020. In a single incident, an attacker reportedly siphoned over $5 million from the community whereas solely spending $192,000 on hashing energy to hold out the assault. Nevertheless, you will need to observe that whereas such assaults stay a risk, community actors can take steps to mitigate the vulnerability.

Associated: If you have a Bitcoin miner, turn it on

Certainly, within the absence of the superior community impact and large hashing energy of Bitcoin, different PoW chains have to create secondary safety protocols to detect malicious blockchain reorgs. To place the hash charge disparity in stark distinction, the overall Bitcoin community hashing energy is presently greater than 320 instances higher than that of Bitcoin SV.

Crypto exchanges additionally want to extend the community affirmation requirement for cash whose chains don’t maintain enough hashing energy. Most 51% attackers try to double-spend their transactions through exchanges, buying and selling their pretend cash for the legit funds held by buying and selling platforms typically on behalf of their customers.

Thus, even when the blockchain does finally struggle off the assault, the hacker can siphon worth from the exploit by buying and selling their pretend cash on exchanges that fail to undertake the mandatory minimal affirmation protocols.