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5 Common Smart Contract Vulnerabilities - How to Handle Them

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By Jaden Francis - - 5 Mins Read


Crypto smart contract vector illustration



Devoid of technical explanations, smart contracts are simply self-executing programs or codes that exist in blockchain networks and protocols.


However, due to its importance in the crypto sphere, it has quickly become the target of cybercriminals, who will patiently wait for any loophole to access it. Illegal access to smart contracts has cost many crypto projects millions of dollars.


But the first step to solving this issue is identifying the problem. This article provides insights into the latest smart contract vulnerabilities and how to mitigate them. Let's dive in!


Access Control Attacks 

Access control attacks make the smart contract vulnerabilities list. When cybercriminals identify flaws in the access control of a smart contract, it can give them access to manipulate many things. Once they spot a defect, they can easily exploit it and gain control over the whole smart contract.


Access control attacks are mainly due to poor security. So the mitigation mechanism for this attack is introducing a robust authentication system before gaining access to a smart contract. A multi-factor authentication security system will be essential in this case. 


Code Vulnerabilities 

Even outside smart contracts, one of the major ways cybercriminals gain access to a system is through code vulnerabilities. A cyber attacker can manipulate a wrong or complicated code to access a smart contract. An effective method of putting a stop to this vulnerability is engaging independent auditors to detect if there's any defect in written code. 


Vulnerable External Contracts 

Sometimes smart contracts will have to make external calls. In other words, they might need to interact and communicate with external solutions and protocols. Assuming such an external protocol has a security vulnerability, it could be extended to the smart contract. Developers should vet an external contract before giving access. 


Reentrancy Attacks 

A cyber attacker can manipulate a smart contract by making it give numerous commands to the smart contract simultaneously. This aims to make the smart contract malfunction before a transaction is complete. Sometimes, this often results in a loss of funds. To prevent this, a smart contract should have an Inbuilt feature that prevents the client-end from triggering multiple calls or commands. 


Integer overflow/underflow

When an integer or variable exceeds the maximum or minimum value, it leads to an overflow or underflow. An effective way to stop something like this from happening is using safe math libraries to handle arithmetic operations. Deploying safe math libraries prevents cybercriminals from exploiting this vulnerability. 


How to Identity and Solve Smart Contract Vulnerabilities?


  • Simulation Attacks 

One of the best ways of knowing smart contract security issues is by creating a real live scenario for an attack. Simulation attack helps developers understand the security vulnerabilities and how to prevent the spread. 


  • Code Auditing and Review

Once the code for a smart contract is complete, the next step is to bring in an independent auditor to review the code. This helps detect any defect with the smart contract programming. MythX, Securify, and Truffle’s built-in security features are some of the tools that might be useful in this case. 


  • Bug Bounty Programs 

Smart contract developers are likelier to make headway when calling community members to help find the bugs. In return for this exercise, they are given incentives. 


  • Implementing Best Practices

Sometimes carelessness with the code and deployment creates loopholes that cyber attackers can use to access a smart contract. Implementing the best code and deployment practices will be very crucial. 


  • Multi-factor Authentication 

The security infrastructure of a smart contract should be around the multi-factor authentication (MFA) method. Furthermore, at least one of the authentication methods should be independent of the client side.