On Saturday morning, the owners and enthusiasts of Lisk cryptocurrencies experienced moments of horror - transactions virtually ceased to be implemented, the network slowed down, and subsequent stock exchanges began to announce that they were holding back LSK deposits and withdrawals on their platforms. The whole situation caused a probable attack aimed at adding false transactions to the Lisk block network.
The situation was possible due to the existence of an extremely difficult to use error in the transaction confirmation algorithm, which allowed a false operation to the block network. The fake transaction has been coded so that the above error can be used, which means that the attacker has previously discovered the problem in the code.
However, Lisk Core has built-in protections to prevent the appearance of false, inappropriately confirmed transactions - nodes have stopped confirming subsequent operations, creating and adding empty or virtually empty blocks to the network, which resulted in almost total network stoppage. Such a radical security is to protect the network from later divisions (forks, known for example from the Ethereum division into ETC and ETH), and first of all from possible losses of funds belonging to LSK holders.
Before the automatic network security system worked, about 150 transactions were confirmed, however, they were suspended and eventually they would be deemed not executed - the network will behave as if they never existed, which means that no one's assets are threatened in any way.
Within a dozen or so minutes of detecting the attack and the emergency response of the network, the Lisk developers started working on an update that will prevent similar security threats and network stops in the future. Update Lisk Core v.0.9.1.5, which restored the network and removed the error in the code was added to the main Lisk repository on Saturday at 12:30. The full range of introduced modifications, as well as the developers' discussion can be traced on the Lisk channel on the Github portal. In connection with the update, delegates (Lisk based on the DPoS consensus algorithm) were asked to update their own nodes as well.
Automatic response of the network to a fake transaction and rapid update of developers prove that Lisk is a serious project with a team of professionals watching over its safety. The course of the whole situation was also quite warmly welcomed by the owners and enthusiasts of Lisk who appreciated such a radical approach to block network security. Currently, all exchanges have already restored the possibility of Lisk deposits and withdrawals.