Top 6 Security Vulnerabilities in Blockchain

The decentralized structure and cryptography underlying blockchain are lauded as the gold standard of digital security but, nevertheless, there are no truly “un-hackable” systems. Therefore, while blockchain technology improves and adapts to new trends (i.e., innovations in cryptography) being used by malicious entities to exploit it, it is critical that developers, investors and companies understand the security challenges associated with implementing and utilizing blockchain technologies. The objective of this document is to examine the various critical vulnerabilities in blockchain security (e.g., vulnerabilities in endpoints, flaws in consensus mechanisms, etc.) so that organizations can implement a more thorough security plan for protecting their blockchain.

Endpoint Security

While the blockchain is itself secure, the endpoints associated with using the blockchain (e.g., wallets, exchanges, devices used by blockchain participants) are typically the weakest link.

Ledger vulnerability points

Most blockchain security vulnerabilities do not exist in the underlying blockchain; rather, they exist at the entry point. Attackers can use malware to gain access to a user’s computer or mobile device and capture sensitive data (such as passwords) before it is encrypted and sent to the blockchain for processing. Once again, phishing is a primary example of how attackers can exploit a user’s computer.

Access risks

Attackers often target the identity and access management (IAM) components of centralized exchanges, or crypto event platforms. When an attacker successfully compromises a user account via social engineering or through credential stuffing, even the best security functions of a blockchain cannot preclude unauthorized transaction activity.

Data feed security

Many blockchain-based solutions leverage external oracles to provide real-time, tangible world data into the blockchain. Unauthorized alterations to these information channels (endpoints) will lead to the smart contract executing based on wrong information and result in very large amounts of monetary loss.

Protection measures

• Establish and implement good security practices when managing your own data; Multi-factor Authentication (MFA) is advisable; and any Private Key ought to be securely stored in hardware wallets that are not internet-connected.
• Instruct blockchain users in identifying phishing attempts.

Key Management

What does it actually mean to keep your own keys? In cryptocurrency, it is often said "If you don't have your keys, you don't have your coins." The most important factor in the protection of your blockchain assets relates to how you handle your private key.

Private key vulnerabilities

A private key is a combination of numerical and alphabetic characters that provide access for you, the owner, by allowing you to approve any transactions. Without the ability to recover your private key, you will be unfit to reclaim your assets; and an individual possessing your private key creates legal ownership of your funds due to their legitimate digital signature.

Common attack vectors

Phishing schemes, clipboard-hijacking viruses, and other attack vectors that hackers will typically use to get access to your private key. Weak security actions will often create an opportunity for a legitimate user's private key to be stored in “hot” (in the cloud) locations, or unencrypted formats/models thus allowing others to target them with extreme ease.

Protection strategies

The preferred practices to secure private keys are contingent on utilizing the "defense-in-depth" philosophy. By defence-in-depth policy, you should be shifting the majority of your funds to cold storage and use multisig (multiple private keys) for authorizing transactions whenever possible.

Best practices

• Do not share your Private Key or Seed Phrase with anyone.
• Establish policies for the management of your business identity and access to blockchain applications.
• Regularly evaluate and revise the identification and access controls used for gaining access to the blockchain.

Code Security

Smart contracts have transformed not just Ethereum but also many public blockchains, but with this technology's rise has come the significant exposure of a new type of vulnerability to human error in the coding of smart contracts.

Smart contract risks

A smart contract is a self-executing, automated contract that executes automatically when certain predetermined conditions are met. If there is a logical error in the code, an attacker could exploit that error to steal all of the liquidity from the blockchain. For example, there are known vulnerabilities such as reentrancy and integer overflows.

Development challenges

In a traditional software environment, it is very easy to fix errors in the code; however, with blockchains being immutable, once a smart contract is deployed, it cannot be easily "patched." 

Testing requirements

Developers of decentralized applications must conduct extensive unit testing and formal verification to ensure smart contracts are secure. The security team must also simulate a variety of different security attacks to understand how the code will behave in terms of edge conditions.

Case studies

The DAO hack on the Ethereum Network is an example of an exploit of a smart contract’s vulnerability and was the most publicized hack of a smart contract, where millions of dollars in ETH were taken from the network and a hard fork of the network took place.

Network Vulnerabilities

The majority of all blockchains have a security model that is based on the assumption that no single entity controls the majority of the mining power or staking on that blockchain network.

51% attack mechanics

If an attacker controls more than 50% of the total nodes or hashing power of the network, the attacker can reverse confirmed transactions and subvert the consensus mechanism of that blockchain.

Double-spend risks

When a hacker gets control of 51% of the blockchain, he can perform a double spend( spending the same cryptocurrency units twice, e.g. Bitcoin) which leads to a diminished amount of trust in the overall security of the blockchain and could result in the total failure of either the bitcoin network, or that of other chains within a similar ecosystem.

Network safeguards

As most large blockchains are very large (e.g., Bitcoin) there is built in resistance against attacks of this kind due to the huge amounts of power needed to conduct mining. However, blockchains that may be smaller, and/or may not have as much mining power to protect against attacks, are at much greater risk of 51% attacks.

Historical incidents

Numerable small blockchain transaction services (e.g., Ethereum Classic and Bitcoin Gold) have been subjected to multiple 51% attacks, proving that the level of decentralization of a blockchain does not guarantee abundance of security when the amount of hash power of that service is very low.

External Factors

No blockchain operates in isolation. Each blockchain system interacts with some sort of third party application (software, API, and/or cross-chain bridge) that will add additional general security issues for the blockchain network.

Third-party dependencies

A large number of blockchain platforms, including IBM Blockchain Platform and many alternative platforms that specialize in generating DeFi services, have been reliant on third party application modules/libraries and/or API. If a vulnerability exists in just one third-party library/module, the host blockchain will become vulnerable.

Security implications

Cross chain bridges (xChain bridges), which are designed to allow transaction activities between two or more blockchains, have also become a significant source of cyber attacks on various blockchain platforms. Between 2022 and 2023, billions of dollars of cross-chain bridges hacks/losses have occurred demonstrating that a security solution must be applied beyond the base blockchain protocol or code.

Provider assessment

Research the provider you intend to utilize for security credibility. All connection points need to be security audited.

Risk mitigation

• Minimize third-party vendor connections through blockchain communication.
• Additionally, perform routine audits of external connections for proper security standards.
• Utilize security planning strategies to look for current network threats in real time.

Conclusion / The Bottom line

The inherent security features of blockchains provide a superior avenue for conducting business; however, they are not unconditionally secure. As an illustration, vulnerabilities exist due to Sybil attacks; additionally, programming bugs may exist in smart contracts. As there are many potential vulnerabilities within the complex world of blockchain security, the solution to those vulnerabilities will result through all parties involved in migrating from the perception of inherent security to diligently implement a comprehensive security plan through continuous monitoring, constant auditing, and improving the security plan.

FAQs

How do endpoint vulnerabilities affect blockchain security?
With endpoint vulnerabilities, an attacker can compromise a device or person connecting to the blockchain. If a device or wallet application is vulnerable, hackers may be able to get access to sensitive information or the private key used to authenticate that information on the blockchain.

What are the best practices for protecting private keys?
Best practices for securing private keys include the following:

• use of hardware or cold wallets;
• enable multi-sig controls;
• do not store private keys in a digital format that is not encrypted.

Proper identity and access control are also critical when an institution uses the blockchain to protect its information.

How can organizations prevent smart contract vulnerabilities?
To mitigate the risk of vulnerabilities in a smart contract, an organization should carry out a code audit of its smart contract application; conduct a review of the code to verify its validity; and use a bug bounty to test the code prior to publishing it on the public blockchain.

What makes a blockchain network susceptible to 51% attacks?
A blockchain network is exposed to a 51% attack as a result of a low total hash rate or mining power. A low total hash rate makes it easier for an attacker to gain majority control and execute a double spend.

How to evaluate third-party blockchain service providers?
To evaluate third-party service providers, the security team should assess historical incidents regarding security breaches, evaluate how the provider manages hashing and node operations. Your chosen provider should be reputable and exhibit transparency with regard to its efficacy and standards in carrying out its security practices.