"On November 30, 2019, a Vertcoin miner noticed a significant increase in the hash rental price of Lyra2REv3 on Nicehash," said Metalicjames, Vertcoin's chief maintenance officer and a MITDCI researcher, at github. This is sent to an unknown (non-public) Vertcoin chunk together with the server connected to Nicehash. I contacted Bittrex, a well-known exchange that trades Vertcoin, and advised them to disable Vertcoin wallets on the platform if they found an attack (and they did so later). The attack took place at 15:19:47 GMT on December 1, 2019, when 603 blocks were removed from the VTC main chain and replaced by 553 attacker blocks. We note that the current confirmation requirement for VTC on Bittrex is 600 blocks. There are 5 "double outputs" where 125 VTCs are redirected. Based on the market price in the preparation of the attack and the difficulty of the attacker in generating chunks, we estimate that the attacker's cost of carrying out the attack is between 0.5-1 BTC. The total value of block awards received is 13825 VCs (-0.44 BTCs). Note that Vertcoin previously suffered a 51% attack in December 2018 and has since changed its workload proof algorithm to Lyra2REv3. "