Jiang Zhuo’er: Attackers Conducted Abnormal Transactions on BCH to Mislead the Public that BCH Upgrade Failed
Bitcoin Cash blockchain faces glitch after the scheduled network upgrade on March 15, as it was noticed that the network was stuck without outputting any blocks after block 582680. The next block, after the update, took about half an hour to be mined.
The Bitcoin Cash chain has split into two chains. A hardfork occurred at block 582,679, however since that block, upgraded and non-upgraded nodes have split onto different chains.
— BitMEX Research (@BitMEXResearch) May 15, 2019
In response to the issue, Jiang Zhuo’er, founder and CEO of the leading bitcoin mining pool BTC.Top, explained that attackers made a bunch of weird transactions on BCH, which resulted in the failure of mining new blocks; BTC.Top has adjusted its BCH hashrate and mined more than 10 blocks after the upgrade (10 confirmations to ensure no rollback). Jiang continued that those abnormal transactions took advantage of a bug in sigops check that caused the pool to make errors in block template creation, but this problem only affected the mining pool in mining new blocks and mining pools have taken measures and will be back to normal soon.
According to Jiang, on May 15, 2019, BCH suffered a premeditated attack which has been resolved in time. The attacker made use of a software bug in the code updated in November 2018 and chose to launch the attack six months later during a scheduled update on May 15, with the intention of misleading the public that the BCH upgrade failed.
The attacker created a number of abnormal transactions, by using this bug, mining pools cannot pack transactions into block. After the attack, BTC.Top, BTC.com and ViaBTC have mined 10 empty transaction blocks in an emergency and used BCH’s anti-reorg protection to ensure that this upgrade will be a success and not be rolled back.
According to PeckShield security, there is some “controversy” surrounding the BCH upgrade. This upgrade is indeed completed successfully. The prolonged outputting time may be due to the fact that some BCH clients have not been upgraded in time, resulting in small hashrate and slow block-producing speed. The security team said there’s the possibility of such attacks as Jiang said, but this malicious attack has no effect on BCH upgrade; there’s a possibility that a malicious attack occurred, in this context, BTC.Top switched its hash power to BCH mining for a short while in an effort to ensure that the malicious block would not become the longer chain.