Research conducted by Saar Tochner, Aviv Zohar, and Stefan Schmid found that a denial-of-service attack could potentially stop the bitcoin lightning network from processing payments. According to the research, the attack is possible because each lightning network payment is passed across a network of nodes in order to reach its destination. And if one of these middle nodes is a bad actor, it can slow the process.
The research further notes that it does not take much to execute the denial of service attack. Aviv Zohar said that it is extremely easy to executive. It takes opening a few lightning channels to key points, promising low or zero fees, and then not relaying any payments, he added.
In the layer two payment protocol, when a user sends a payment across, their app decides which path to take based on many factors, including which node requires the lowest fees. According to Zohar, to execute a DOS attack, you would need around 20 or so new channels to influence 80% of all transactions, and it would only cost around $2,000.
Alex Bosworth, who is the infrastructure lead at the Lightning Labs, said that it’s something hard to talk about as they are still developing the path-finding system in LND, and its a moving target.