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Ethereum Is Under Attack

The cryptocurrency is going through some growing pains.
Image: Flickr/David Howard

On Thursday, virtual currency and so-called "world computer" Ethereum announced that its network is under attack, causing the network to slow down and making for a big headache for users.

The announcement comes just days after Ethereum alerted users to a denial-of-service (DoS) attack that caused the currency's clients to run out of memory and crash. A fix for the bug that allowed the attack was quickly released.


It's unclear who is behind these attacks, or what they're after. Is someone trying to make a buck on the currency's value dropping, as one commenter speculated? Or is someone just fomenting chaos for the hell of it? If similar attacks on Bitcoin in the past are any indication, we may never know for certain.

Read More: I Broke Bitcoin

What we do know, according to a blog posted by Ethereum on Thursday, is that the ongoing siege is a DoS attack designed to strain the resources of computers running Ethereum. The attack exploits a feature that forces Ethereum transactions to check the code of other transactions in the network. These checks cost "gas," a unit that Ethereum users must spend to perform an action on the network, but not much. By putting a lot of gas behind a transaction, one can be forced to make these checks an inordinate number of times.

"The attack transactions are calling this [code] roughly 50,000 times per block [of transaction data]," the Ethereum blog post states. "The consequence of this is that the network is greatly slowing down."

This state of affairs is negatively affecting some users. One prominent Ethereum mining pool, wherein individual users combine their computer resources to "mine" blocks of Ethereum transaction data for an automated reward, currently states at the top of its homepage that payouts are suspended until the issue with the Ethereum network is resolved.


These issues are familiar to bitcoin users, the most popular virtual currency that shares some similarities with Ethereum, is frequently under fire from DoS attacks sent by anonymous parties with inscrutable motivations, whether financial or ideological. These attacks, while briefly annoying for many users, are usually not harmful in the long-term.

Ethereum is also no stranger to network attacks, and the current spate of DoS hijinx are far from the worst of them.

In June, a massive user-directed investment fund worth $56 million running on Ethereum had most of its funds siphoned away by a hacker who exploited a glitch in the code-based "smart contract" that governed how the fund operated. This hack required a hard fork in Ethereum to roll back the damage, creating two versions of the virtual currency that are now in competition.

If this keeps up, Ethereum might become just as interesting as Bitcoin in terms of shenanigans, albeit for reasons that will probably be unwelcome to anyone with money on the line.

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