Forked Bitcoin Cash Chain Under DoS Attack

Vishal Chawla

Nov. 24, 2020

Shortly after the newly-forked Bitcoin Cash ABC (BCHA) network went live, an unknown miner disrupted the network by mining empty blocks.

DeFi Forks Will Struggle Because You Can’t Fork Community

Key Takeaways

The newly created Bitcoin Cash ABC is under a DoS attack.
The attack originated from an unknown miner which has been mining empty blocks for more than a week.

Bitcoin Cash ABC (BCHA), the result of the recent Bitcoin Cash (BCH) hard fork, has witnessed an attack where a single miner is disrupting the network.

Bitcoin Cash Fork Under Attack

Experts are calling it a denial of service (DoS) attack aimed at disrupting the blockchain.

The attack originated from an unknown mining entity that has been mining empty blocks on the Bitcoin Cash ABC chain for more than a week.

The attacker broadcasts mysterious message: /Nov 25th 2020: bcha dump/ — The attacker broadcasted a mysterious message: /Nov 25th, 2020: bcha dump/. Source: Blockchair

An empty block only contains the block reward transaction (as seen above), and all other transactions are excluded, hampering the network to function normally.

The incident was first reported by Nikita Zhavoronkov, the lead developer at Blockchair, who said it is clearly malicious behavior.

I don’t wain to rain on the Bitcoin ABC’s parade, but my prediction was correct — the chain just got DoS attacked. There are 200k transactions in the mempool waiting to be confirmed, and someone mined 11 empty blocks — it is clearly malicious behaviour. pic.twitter.com/xhp73f3c0w

— Nikita Zhavoronkov (@nikzh) November 21, 2020

The intention behind the attack is still unknown. Adding to the mystery, the attacker also broadcasted a message which warned of an upcoming “bcha dump” on Nov. 25.

Low Hash Rate, Few Miners Led to the Attack

On Nov. 15, a Bitcoin Cash (BCH) blockchain fork took place, resulting in a new blockchain called Bitcoin Cash ABC (BCHA). After the BCHA chain went live, only a few mining pools were active, resulting in a low network hashrate.

The unknown miner has the biggest hash rate on BCHA. Source: Blockchair

At press time, BCHA’s hashrate is 0.12 Eh/s, which is less than 1/10th compared to BCH’s hashrate of 1.7 Eh/s. According to Zhavoronkov, the low hashrate may have allowed a single mining group to control the network.

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