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What are the various attacks that are possible on a blockchain?

The blockchain industry is on the precipice of explosive growth, with a projected revenue to recognize emerging trends related to blockchain security.


A blockchain is a digital ledger of all cryptocurrency transactions. It is constantly growing as “completed” blocks are added to it with a new set of recordings. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data. Bitcoin nodes use the blockchain to differentiate legitimate Bitcoin transactions from attempts to re-spend coins that have already been spent elsewhere.

There are a few different types of attacks that can be carried out on blockchain technology:

There are several possible attacks on blockchain technology, including:

51% Attack: A 51% attack refers to an attack on a blockchain by a group of miners who control more than 50% of the network’s mining hash rate or computing power.

Sybil Attack: A Sybil attack is when a malicious user creates multiple fake identities to gain control of a network or influence its decisions.

Denial-of-Service Attack: A denial-of-service attack is when a malicious actor attempts to flood a blockchain with so much data that it can no longer function properly.

Eclipse Attack: An eclipse attack is when a malicious user or group of users is able to isolate a particular node on a blockchain network and prevent it from communicating with the rest of the network.

Race Condition Attack: A race condition attack is when a malicious actor attempts to exploit the fact that multiple nodes often operate blockchains to gain an unfair advantage.

Double-Spending Attack: A double-spending attack is when a malicious user tries to spend the same digital currency twice.

Blockchain Forking Attack: A blockchain forking attack is when a malicious actor attempts to create a fork in the blockchain to reverse transactions or disrupt the network.

Pennsylvania Attack: A Pennsylvania attack is when a group of miners colludes to control more than 50% of the mining power in a Proof-of-Work blockchain network.

Selfish Mining Attack: A selfish mining attack is when a group of miners withhold their blocks from the network to increase their profits.

Timejacking Attack: A timejacking attack is when a malicious user attempts to manipulate the timestamp of blocks to disrupt the network.

How to protect against blockchain attacks?

There are several ways to protect against blockchain attacks, including:

  1. Use a strong and unique password for each account.
  2. Never reuse passwords.
  3. Use a password manager.
  4. Use two-factor authentication whenever possible.
  5. Keep your software up to date.
  6. Use a reputable antivirus program.
  7. Use a firewall.
  8. Be cautious when downloading files from the internet.
  9. Don’t click on links in emails or text messages from unknown senders.
  10. Avoid public Wi-Fi networks.

To conclude

Blockchain is a secure way of storing data, but like any other technology, it is not perfect, and there are ways to attack it. However, following the above tips can help protect yourself from these attacks.

iTrust provides a cyber security risk assessment for Private, Consortium, Hybrid, and other blockchain networks.  

iTrust uses comprehensive and detailed risk assessment techniques that can be used to evaluate the security of blockchain networks. Our solution focuses on providing the highest level of infrastructure vulnerabilities detection, increasing a separate node’s security.