A crypto project known as Vertcoin, that works for the purpose of keeping mining power decentralized, has suffered another second 51-percent attack in a year.

According to James Lovejoy, the project's lead maintainer, in a GitHub notice said  " the incident saw 553 blocks written by the attacker being replaced with the genuine 603 blocks on the Vertcoin. This incident took place on Sunday, 1st  Dec.  The blockchain reorganization caused five "double spends" to the value of 125 vertcoin (VTC) worth approximately $29. " he added.

“It was noticed that each of the double-spent outputs are actually outputs owned by the attacker and though it is unknown to the original recipient of the coin, then after the reorgs, the coins will be pushed to an attacker address, " Lovejoy stated.

Explaining 51% Attack 

when an entity or entities as the case may be gains over half of the hashing power of a blockchain network, thereby making it possible or rendering the ability to rewrite the blocks making up the "chain, we can say a 51-percent attack has  taken place. "

Vertcoin has experienced another 51-percent attack almost a year ago from today that caused multiple reorgs and this was estimated by Coinbase to have cost users over $100,000.

 According to Lovejoy, “Vertcoin switched its proof-of-work algorithm to this one known as Lyra2REv3 as they  aim to block powerful mining chips called ASICs from the network to push it towards  mining more community based and affordable – after the attack. They latest attack may have been seen coming from the look of things.”

A Vertcoin miner had noticed on Nicehash,  a large upswing in hashrate rental prices for Lyra2REv3 on Nov 30th 2019,  . Nicehash's stratum server was sent work for unknown (non-public) Vertcoin blocks with a combination of workers connected to it.

It was then that  Bittrex -Vertcoin's most prominent exchange was alerted,  to recommend they disable the Vertcoin wallet on their platform which they did as soon as it became clear that an attack was in progress.

The developer continued to maintain his speech, “there's 'strong evidence' that by harnessing leased hashrate from Nicehash, that the attack was carried out. 

"Through the process of inspecting the work being sent from Nicehash's stratum servers, which were sending work for non-public blocks, the attack was actually discovered from the beginning " he said.

Meanwhile. It's still not clear the reason for Vertcoin  second attack. Lovejoy said it would not have been profitable based on miners' block rewards alone.  Bittrex may have been the target actually , but more double spends may have been prevented by the exchange disabling its Vertcoin wallet,  He suggested. 

The attack may have been "a proof of concept or sabotage attack." An alternative option is that thefts through double spending was not the plan anyway. 

Credit: Daniel Palmer