(Defense Against) The Dark Arts - Contract Runtime Mutability

Smart contracts are no longer guaranteed to have immutable runtime code, and can be redeployed with new code using a variety of methods involving the CREATE2 and SELFDESTRUCT opcodes. In this presentation, we will investigate how this is done and how to protect against malicious mutable contracts. We will also explore ways these new techniques can be applied in order to enable new use-cases and to improve the user experience.

Fuzzing the Solidity Compiler

Since the Solidity programming language does not have a formal specification, testing the compiler implementation is an important way to obtain assurance about the correctness of code generated by the compiler. Fuzz testing is well-suited for this setting. However, applying fuzzing in the traditional manner (random input generation that is coverage-guided) is inefficient for testing compilers because a significant fraction of randomly generated code is syntactically invalid. If the fuzzer does not generate syntactically correct Solidity programs, the compiler will simply reject it. As a consequence, code optimization and generation subsystems of the compiler will not be tested. The approach adopted by us is to define a grammar for the Solidity programming language and automatically generate inputs based on this grammar. Grammar based fuzzing ensures that generated programs are successfully parsed by the front-end parser. We make use of libProtobuf and libProtobufMutator for defining the grammar and performing grammar-based mutations, and libFuzzer as the underlying fuzzing engine.

Keymanagement: Multisig based Custody as Enabler for Mass Adoption

Key management is a fundamental challenge in the widespread use of blockchain technology. Especially when it comes to managing large tokenized values, a suitable custody service is essential. While many existing custody services are primarily based on technologies such as Shamir's Secret Sharing, it makes sense to use a Smart Contract based Multisig to manage the rules such as access, what signatures are required, time delay, recovery of lost accesses, etc.

Securely storing wallet private keys for application use

Private key management is a complex problem in cryptography. In the last few years, we have seen attacks against cryptocurrency companies that seek to retrieve the private keys of user wallets. Within cryptocurrency, private key management has an additional complexity: the value of stored user funds related to that private key. Truly, key management is a challenge that has plagued secure computing for years.While storing keys is essential, it is equally important to securely use those keys in an application. Without secure use of private keys, applications are vulnerable to attacks to exfiltrate those private keys.In this talk, we will discuss the approach the AirSwap team uses to securely store and use private keys for high value wallets. We will show real world permissions, policies, and code used by our team. We will discuss common attacks against private key management systems and the ways that our implementation thwarts those attacks.This talk is beneficial to any team or company that interacts with the Ethereum blockchain via signed transactions and off-chain custom code. It is essential for any team that wishes to use a private key in their application code securely.

The inner workings of a smart contract decompiler

The workshop will teach some of the most useful algorithms and tricks needed to analyse and decompile an EVM smart contract: symbolic execution, memory modelling, loop handling and so on.Techniques shown during the workshop are useful in anything related to contract analysis - from writing your own decompiler, through using existing tools like Eveem, Mythril or Manticore, to working with formal verification K Lab style. Based on the experience from building Eveem.org decompiler and analysing all the bytecodes on the Ethereum blockchain.

Protecting The Baselayer - from Shanghai to Osaka

Most people know that Ethereum runs smart contracts and move ether around. However, "Ethereum Security" involves a lot more than only smart contracts, mining difficulty and managing private keys. This is a talk about the base layer security. There is a peer-to-peer stack, with it's own separate discovery protocol and p2p protocol, which can be used for eclipse-, DoS- and amplification attacks. There's a consensus engine which encompasses a lot more than only the EVM. In this talk, Martin Holst Swende will talk about vulnerabilities, attacks and hotpatching the mainnet -- lesser known incidents, hiccups and close-calls that have occurred on the road from Shanghai (Devcon2) to Osaka (Devcon5).

ERC 20 Test Suite: Towards Decentralized Security

Nowadays, a lot of Dapps and exchanges interact with ERC20 tokens and they expect certain behavior from those contracts. It is crucial to make sure that the token fully complies with ERC20 standard to avoid loss of funds and reputation. The problem is that one cannot easily verify this compliance. This can be done only by ordering an audit or writing and running a bunch of tests. However, these options are expensive and not scalable. In my speech, I will tell about a decentralized tool that we created to help developers solve such problems. ERC20 Test Suite is a service that runs a series of tests for ERC20 standard compliance in the form of on-chain transactions. The final test results are recorded in a smart contract. Test Suite cannot fake the test results as each test is a transaction recorded in the blockchain. SmartDec ERC20 Test Suite is open source: https://github.com/smartdec/testsuite Also, we have deployed our centralized instance of the tool here: http://testsuite.net/ropsten/

Ethereum Security

Martin Swende gives their talk on Ethereum Security.

Evolution of Smart Contract Security in the Ethereum Ecosystem

A lot has changed in the smart contract development ecosystem in the year since DEVCON2. Our perspective as leaders of the smart contract security community OpenZeppelin shows us that the industry is maturing. We give a brief overview of how security patterns and practices have evolved in the past months, dive into some details of recent developments, and talk about promising projects and their plans for the future.

The Melon security approach

Melonport is striving to build a vibrant and successful developer ecosystem of Melon module builders. An important part of that ecosystem is the security and behaviour of smart contracts that make up Melon modules as well as how they interact with the Melon core and each other. In this presentation, we’ll demonstrate our ongoing technical efforts to assist Melon module developers in creating safe, secure smart contracts and touch on the importance of getting the auditing process right and how others can learn from our experience.