Statement on August 2021 block re-organisation attack on the Bitcoin SV network

The Bitcoin SV network is currently enduring an ongoing series of block re-organisation attacks by a malicious actor attempting to illegally double-spend BSV coins. Bitcoin Association believes that this is the same attacker that previously initiated block re-organisation attacks against the BSV network on June 24 and July 1, 6 & 9, 2021.

To prohibit fraud and eliminate the benefits of all illegal activity by the attacker – including the block re-organisations and attempted double spends – it is the recommendation of Bitcoin Association and the Bitcoin SV Infrastructure Team that honest node operators mark the illegal chains initiated by the attacker as invalid.

In parallel, Bitcoin Association continues to collect evidence of the illegal activity and its representatives are actively working with law enforcement authorities in affected jurisdictions.

This page will continue to be updated with relevant and important information regarding the attack.

Update – 05/08 – 9:30am (GMT +1)

The third attempted attack on the network has been successfully repelled. The attacker again created an illegal fraudulent chain, which can be identified as:

Attack 3

Chain: 0000000000000000085e09942ff3af4282d90ec5d2f566294b2a0e0f6c246501
Height: 698815
Timestamp: 1628049139

As of the time of posting, there have been no further attempted attacks on the network.


Update – 04/08 – 11:30am (GMT +1)

In the last 12 hours, two illegal chains created by the attacker have been successfully repelled:

Attack 1

Height: 698642
Timestamp: 1627922346

Attack 2

Height: 698737
Timestamp: 1628002897

In an effort to continue their illegal activity, the attacker is now attempting to start a third fraudulent chain. In order to ensure that your node is following the honest chain, we again recommend marking the fraudulent chains as invalid.

Attack 3

Height: 698815
Timestamp: 1628049139

To invalidate the fraudulent chains, node operators should run the following commands on their Bitcoin SV node:

bitcoin-cli invalidateblock 000000000000000003B67AEC95E9B5DA897EB5EBF3227D5A6A67835104367840


bitcoin-cli invalidateblock 0000000000000000093f564e9849e80b7d043ebf72a75b57b849fad3d23d27d7


bitcoin-cli invalidateblock 0000000000000000085e09942ff3af4282d90ec5d2f566294b2a0e0f6c246501

This will immediately return your node to the chain supported by honest miners and have the effect of locking the attacker’s fraudulent chain out.

This is an ongoing situation and we believe that it is likely that the attacker will continue to attempt to illegally create fraudulent forked chains. As such, it may be necessary to repeat this procedure to continue invalidating illegal chains.

Bitcoin Association and the Bitcoin SV Infrastructure Team continue to monitor the situation around the clock; however, it remains critically important that infrastructure providers and ecosystem partners continue to invalidate illegal forked chains to protect the network and its users.

We believe that exchanges should implement these measures as best practice whenever fraudulent chains with attempted double-spend transactions are detected; these actions are illegal on any blockchain and with any digital currency, not just on BSV.

Please continue to follow this page, as well as Bitcoin Association social media accounts to stay up-to-date and informed of the latest news in this ongoing situation.

For any questions, queries or inquiries, please contact [email protected] 

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