Following the recent sustained DoS attack, Ethereum has announced an imminent hard fork for EIP150 gas cost changes.

On 22 September 2016, Ethereum announced that it was under a computational distributed denial of service attack (DDoS), which caused slowing down of the network. In the recent announcement, Ethereum said that “the attacker[s] have been very crafty in locating vulnerabilities in the client implementations as well as the protocol specification.”

Earlier this month, Gavin Wood, founder of Ethcore, said that the protocol is flawed and called for a reparatory hard-fork as soon as possible.

Ethereum said that although the recent patches have led to an overall increased resiliency in the client implementations, the attacks also highlighted a need for a lower-level change to the EVM pricing model. It has been decided:

• “As a temporary measure to minimize the effects of the most recent attack, we recommend all miners to lower the gaslimit to 500K gas.
   
• A hard-fork based on EIP 150 version 1c will be put into effect at block 2457000. This will reprice certain operations to correspond better to the underlying computational complexity.
   
• A second hard-fork will follow shortly after, aimed at reverting the current “state-bloat” introduced by the attacks. This second fork will serve to remove accounts which are empty; lacking code, balance, storage and nonce == 0.”

Ethereum Developer Jeff Wickle confirmed that consensus has been reached to hardfork, with the Go Ethereum client to be released soon, CryptoCoinsNews reported. The hardfork code has been under development for past couple of days and is currently undergoing review and testing.

“The EIP150.c1 hard fork is being targeted for Monday. We have a candidate branch and will be releasing a fork-ready client as soon as there are proper consensus tests. This should address the underlying issues in the protocol. Until then I fear it might be a bit of a bumpy ride as the attacker gets ever more cunning in their exploits of these flaws”, Wood said, as quoted by CryptoCoinsNews.

The entire network is expected to upgrade within two-three days once the hardfork clients are released.