Vertcoin chief maintainer: Vertcoin (VTC) has suffered a 51% attack

Vertcoin chief maintainer and MITDCI ​​researcher metalicjames said on github: "On November 30, 2019, a Vertcoin miner noticed a significant increase in the price of the lease of Lyra2REv3 on Nicehash. This was sent to the unknown along with the server connected to Nicehash Non-public) Vertcoin block. I contacted Bittrex, a well-known exchange that trades Vertcoin, and advised them to disable the Vertcoin wallet on the platform once they found an attack (they did the same later). This attack occurred in December 2019 At 15:19:47 GMT on the 1st, 603 blocks were removed from the VTC main chain and replaced by 553 attacker blocks. We noticed that the current VTC confirmation requirement on Bittrex is 600 blocks. Yes 5 "dual outputs", of which 125 VTCs were redirected. Based on the market price during the attack preparation process and the difficulty of the attacker to generate blocks, we estimate that the attacker's execution cost is between 0.5-1 BTC. The total value of the block rewards received is 13,825 VTC (~ 0.44 BTC).
Note: Vertcoin was also attacked by 51% in December 2018, and then changed its proof-of-work algorithm to Lyra2REv3. "