Blockchain technology powers many cryptocurrencies and decentralized networks today. For these systems to work, they must always stay secure and available. A major threat is DDOS attacks, where networks get flooded with fake traffic to crash them. If a blockchain network goes down from an attack, transactions can’t go through, mining stops working, and other big problems can happen.
In this blog, we will discuss different ways attackers DDOS blockchain networks. We will also cover techniques for blockchain developers and users to guard against these attacks better. This includes rate limiting, proof-of-work, restricting smart contract resources, and more.
The goal is to help anyone working with blockchain understand DDOS risks and learn simple ways to make their decentralized networks more resilient against attacks.
What are DDOS attacks on blockchain, and how does it work?
A distributed denial-of-service (DDOS) attack occurs when a blockchain network is flooded with fake traffic all at once, overwhelming and crashing it. These attacks work by leveraging multiple infected devices to hit the target from all angles.
For example, a botnet with thousands of devices under the control of the attacker is used. The attacker sends commands for the whole botnet to start sending meaningless requests to blockchain nodes simultaneously. This floods the network with junk traffic, overloading servers, clogging up bandwidth, and preventing regular users and transactions from getting through.
Prominent examples of DDOS attacks on blockchains include:
- Crashes of the Ethereum network in 2016 and 2022.
- A series of attacks on Bitcoin in 2013 causing temporary transaction delays.
- A 2022 attack on Solana was coordinated through Discord to overwhelm the network repeatedly.
The main goals of DDOSing a blockchain are usually either for the attacker’s financial gain, by profiting from bets on crashing prices or double spending, or to damage network operations and reputation during peak periods of activity.
Evolution of DDOS Attacks on Blockchain Networks
In the early years of blockchain technology, distributed denial-of-service (DDOS) attacks were less sophisticated and widespread. When Bitcoin launched in 2009, minimal infrastructure was in place for DDOS defense. However, as cryptocurrencies grew in value and blockchain networks saw higher activity, they increasingly became targets.
Major DDOS attack case studies on blockchains include crashes of the Ethereum network in 2016 and 2022, a series of Bitcoin attacks in 2013 delaying transactions, and a 2022 attack on Solana repeatedly overwhelming it. As the impact of these incidents illustrated vulnerabilities, improving blockchain security measures against DDOS threats became a priority.
Over time, common attack vectors like transaction flooding, node overload attacks, and reflection techniques have advanced as blockchain protocols evolve. For example, the shift to proof-of-stake consensus in Ethereum made novel protection necessary. Developing effective DDOS attack prevention has required continuous blockchain network resilience through adapting defensive systems.
To harden infrastructure, popular DDOS defense tactics used today include rate-limiting transactions, throttling connections, implementing standards like proof-of-work for validation, adding delays in peer discovery processes, isolating nodes based on activity levels, restricting smart contract resources to prevent exploitation, deploying intrusion detection systems and firewalls, leveraging global CDNs to absorb traffic, and more.
While these measures help, DDOS threats also continue to grow in scale and sophistication. Attackers now leverage botnets with hundreds of thousands of devices, refractive techniques that disguise original sources, and new strategies like repeatedly depositing and withdrawing funds from exchanges to clog traffic. As long as financial incentives exist, hackers will invest in new ways to overwhelm systems.
Maintaining robust DDOS defense for blockchain networks requires continuous awareness of emerging attack vectors, quickly deploying security updates as vulnerabilities are discovered, collaborating across protocols to share threat intelligence, and instilling best practices in blockchain software design and user behavior. The ongoing race against ever-evolving DDOS threats demands vigilance through proactive improvement of prevention capabilities.
7 Steps to protect blockchain networks from DDOS attacks
Here are 7 steps to safeguard blockchain networks from DDOS attacks:
1. Implement rate-limiting
Rate limiting means limiting the number of transactions or data that can flow through the blockchain network in a certain period. This can prevent traffic spikes from overwhelming the system resources during an attack.
For example, the Ethereum network sets gas limits for how many transactions can happen per block. This helps prevent bottlenecks when activity increases suddenly, either naturally or maliciously. Other examples would be putting limits in peer discovery protocols, restricting how many nodes a peer can connect to at once.
2. Use Proof Systems like Proof-of-Work
Proof-of-work requires senders to do some work that takes computational resources before making transactions. This makes flooding attacks more expensive for attackers since each junk request now has an associated cost to get validated. It acts as an economic deterrence.
Most cryptocurrency blockchains rely on proof-of-work systems to validate transactions and add blocks. However, new protocols could consider adopting their own versions to raise the difficulty of attackers and create friction against traffic spamming attacks.
3. Deploy Intrusion and Detection Systems
Intrusion detection systems monitor network activity to rapidly detect anomalous patterns indicative of an ongoing DDOS attack while allowing normal traffic through. This allows quick responses before significant disruption happens, like blocking malicious IP ranges.
For example, blockchain analysis firms like Chainalysis offer DDOS defense systems working across protocols to identify and filter out surges of attack traffic in real time. Leveraging these as blockchain security measures provides broader threat visibility.
4. Improve the Resilience of Nodes
Individual blockchain nodes can also implement their own DDOS resilience measures locally against traffic flooding. Options include blocking IPs based on requests per minute thresholds, maintaining upstream bandwidth overhead, running only core processes, putting sockets behind proxies and load balancers, etc.
Improving node-level defense reduces the attack surface available for attackers to exploit. Best practices should be spread across node operators to harden infrastructure against overload attacks, which aim to take down critical network channels.
5. Cultivate Strong Community Coordination
Effective DDOS attack prevention ultimately requires coordination among blockchain network administrators, developers, users, and other stakeholders who share intelligence. Developing robust channels for communicating threats, distributing security updates to address vulnerabilities, collectively documenting attack case studies, and executing decisions to enhance defenses can contain attacks.
Cross-chain taskforces against DDOS threats should foster practices like responsible disclosure of bugs/loopholes, transparency in cases of disruption, contingency protocols during incidents, and incentivizing ethical hacking to stress test resilience. Nurturing shared responsibility strengthens the blockchain ecosystem’s overall security posture.
6. Deploy Global CDN Caching
Content delivery networks (CDNs) work by distributing caching servers globally to absorb and mitigate traffic floods before they reach blockchain networks. Major DDOS attacks often leverage botnets spanning thousands of compromised devices that are geographically dispersed.
By deploying CDN caching layers with points of presence spread widely across regions near users, the impact of traffic floods can be effectively absorbed without congesting blockchain infrastructure. Global caching essentially acts as a cushion against spikes in requests.
For example, Cloudflare offers DDOS protection and CDN services used by prominent blockchain providers such as Cryptocompare and Blockchair to enhance resilience. Distributing traffic loads worldwide makes CDNs a versatile blockchain security measure.
7. Implement Limits in Smart Contract Execution
Attackers can sometimes exploit smart contracts executing on blockchains to trigger excessive computation, data storage bloat, infinite loops, and other wasteful procedures that overload resources.
By instituting caps and dynamic throttling on resources usable in contract execution based on the type of operation, bandwidth availability, account history, and reputation, the fallout from contractual exploits can be contained.
For example, limiting total compute units per block, restricting storage of oversized data, turning off recursion/loops beyond reasonable depths, and sandboxing untrusted contracts are some ways protocols architects can harden resilience against smart contract DDOS triggers.
Rounding Up – DDOS Attacks on Blockchain
As blockchain networks underpin critical financial and technical infrastructure, ensuring their security and availability is imperative against threats like distributed denial-of-service attacks.
Implementing proactive protections by continuously improving rate-limiting policies, instituting strict proof systems, deploying intelligent detection solutions, coordinating global CDN caching, restricting risky smart contract behaviors, and more can effectively harden resilience.
However, the accelerators in this arms race are financially and ideologically motivated attackers who will persist in developing ever more sophisticated methods to sabotage networks.
Sustaining robust defenses thus requires constant vigilance through vulnerability testing, regular stress testing of systems to meet scaling demands, sharing actionable threat intelligence between stakeholders worldwide, and cultivating internal blockchain expertise across security domains on par with offensive adversaries.
By treating resilient design as interdependent with consistent software updates, knowledge sharing, and matched investment in talent, we can stay ahead of sophisticated blockchain attackers in the long run.