‼️#BCH /#bcash was hit by 51% attack from just 2 miners, http://BTC.TOP  & http://BTC.com
- & no one seems to be talking about it. 🤨 Thread 👇🏻
1/  What I've gathered from loose details:First, there was an unintentional split with the recent #BCH "upgrade."

2/Since the original split in 2017, there has been a significant number of coins accidentally sent to "anyone can spend" addresses (due to tx compatibility of sigs, but no #SegWit on #BCH), or possibly they've been replayed from #Bitcoin onto the #BCH network.

3/Because of this, tons of coins (#BCH) would essentially be "up for grabs." However, devs implemented a protocol rule called CLEANSTACK, making P2SH coins unspendable.
This was to be removed with May 15 fork, basically handing the coins to miners. https://github.com/bitcoincashorg/bitcoincash.org/blob/master/spec/2019-05-15-upgrade.md

4/During the unintentional fork, someone exploited a bug (details are really hard to find) to add invalid TXs to @Bitcoin_ABC's client mempool. To counter, http://BTC.TOP  mined empty blocks (the bad TXs made blocks impossible to produce) coinspice.io/news/unknown-attacker-fails-to-disrupt-bch-upgrade

5/Due to low hash rate of the network, http://BTC.TOP  actually controlled over half (~54%) of #BCH hash power. Putting them in a position to essentially dictate which blocks were accepted by the network. (we'll see the problem here in a sec) https://bitcoinexchangeguide.com/is-bitcoin-cash-under-a-51-percent-attack-as-one-bch-mining-pool-nears-over-half-control/

6/ In the confusion, an unknown miner (possibly the attacker, but unconfirmed) tried to snatch a bunch of P2SH/#Segwit coins.  But http://BTC.TOP  & http://BTC.COM  were expecting, and/or preparing to recover SegWit coins themselves...https://honest.cash/kiarahpromise/sigop-counting-4528

7/According to discussions, http://BTC.top  and http://BTC.com  were working with another party to recover #SegWit coins to rightful owners (exchanges and/or users).
How they sourced the rightful owners I'm not sure, but this appears to be "reddit consensus.

8/ When the unknown miner tried to take the coins themselves, http://BTC.TOP  & http://BTC.COM  saw & immediately decided to re-org & remove these TXs, in favor of their own TXs, spending the same P2SH coins, + many others.  https://honest.cash/kiarahpromise/sigop-counting-4528

9/It apparently took hours to figure out what happened as none of this was public yet. It appears the 2 miners were ready & communicating with each other directly & possibly another party (exchange or devs) for coordinating the re-org. Cant find specifics from involved parties.  https://pbs.twimg.com/media/D7WMLRhXoAAzlEd.jpg

10/So just 2 miners, in secret & w/ no trouble, took it upon themselves to remove 2 blocks w/ another’s TXs, & replace with their own. Bizarrely, some are celebrating!
Some devs are quiet, but jtoomim (#BCH dev) called it “justice,” & “punishment” for “antisocial behavior.”  https://pbs.twimg.com/media/D7WM4hNXkAAfAsu.jpg
  https://pbs.twimg.com/media/D7WM5NGW0AALecm.jpg

11/One dev seems to be actually discussing how dangerous of a precedent this was & has the only write-up that I can find so far on what exactly occurred. #BCH
https://pbs.twimg.com/media/D7WNXlnW0AACJqw.jpg

12/This is what everyone warned about of endless HFs. Its an attack vector, kills Lindy effect, & has turned #BCH into a political mess where private comms control what does/doesn't get in a block. I can’t tell if no one cares, or if they just want to ignore it?

13/There are at least a few people (maybe only partially) realizing that this basically kills any perception that #BCH is "decentralized, censorship resistant money."  And leaves them to fight over whether the miners are "good guys" or "bad guys" with their actions. https://pbs.twimg.com/media/D7WOrXcWkAE2EA3.jpg

14/Very curious to see others who could dig further (& more thoroughly) into this, as details are not easy to find, & there seem to no articles about the 51% as far as I can tell. 😁
/fin