SmartCheck

Abstract

Ethereum is a major blockchain-based platform for smart contracts -Turing complete programs that are executed in a decentralized network and usually manipulate digital units of value. Solidity is the most mature high-level smart contract language. Ethereum is a hostile execution environment, where anonymous attackers exploit bugs for immediate financial gain. Developers have a very limited ability to patch deployed contracts. Hackers steal up to tens of millions of dollars from flawed contracts, a well-known example being "The DAO", broken in June 2016. Advice on secure Ethereum programming practices is spread out across blogs, papers, and tutorials. Many sources are outdated due to a rapid pace of development in this field. Automated vulnerability detection tools, which help detect potentially problematic language constructs, are still underdeveloped in this area.We provide a comprehensive classification of code issues in Solidity and implement SmartCheck -an extensible static analysis tool that detects them 1 . SmartCheck translates Solidity source code into an XML-based intermediate representation and checks it against XPath patterns. We evaluated our tool on a big dataset of real-world contracts and compared the results with manual audit on three contracts. Our tool reflects the current state of knowledge on Solidity vulnerabilities and shows significant improvements over alternatives. SmartCheck has its limitations, as detection of some bugs requires more sophisticated techniques such as taint analysis or even manual audit. We believe though that a static analyzer should be an essential part of contract developers' toolbox, letting them fix simple bugs fast and allocate more effort to complex issues.

Defects and Vulnerabilities in Smart Contracts, a Classification using the NIST Bugs Framework

“…We considered any two bugs as duplicates if they came from two different sources and described the same issue. Once our comprehensive master list was constructed, we organized the bugs further according to prior research by Tikhomirov et al [8]. This places each bug into one of four categories: security, functional, developmental and operational.…”

“…Trailing Bitcoin, Ethereum, as of June 2019, is the second most popular cryptocurrency by market value [3]. Contrary to traditional distributed applications, Ethereum operates in a permission-less network where arbitrary participants can join [8]. Although these participants must adhere to a predetermined protocol within the Ethereum environment, there is still substantial opportunity for manipulation of the smart contracts that reside on the network.…”

“…Owner privileges are not utilized, yet they are required for the state of the contract to change; this situation causes the contract to fail. [8,13,14].…”

“…It defines a list of rules for Ethereum tokens. If the ERC-20 standard token interface is not met, then the contract will not be able to trade its currency with others [8].…”

“…Looping over a resource-intensive function can cause the contract to lose all of its gas [8]. Cause: A loop containing a resource-costly function.…”