Elusive Thoughts

Introduction  This article is going to focus on Smart Contract upgradability, why this important and how can we achieve it. When dealing with Smart Contracts we need to be able to upgrade our system code. This is because if security critical bugs appear , we should be able to remediate the bugs. We would also want to enhance the code and add more features. Smart Contract upgradability is not as simple as upgrading a normal software due to the blockchain immutability.   As already mentioned by design, smart contracts are immutable. On the other hand, software quality heavily depends on the ability to upgrade and patch source code in order to produce iterative releases. Even though blockchain based software profits significantly from the technology’s immutability, still a certain degree of mutability is needed for bug fixing and potential product improvements.   Preparing for Upgrades    In order to properly do the upgrade we should be focusing in the followi...

 Introduction  As Crypto currency technologies are becoming more and more prevalent, as the time is passing by, and banks will soon start adopting them. Ethereum blockchain and other complex blockchain programs are relatively new and highly experimental. Therefore, we should expect constant changes in the security landscape, as new bugs and security risks are discovered, and new best practices are developed [1].This article is going to discuss how to perform a source code review in Ethereum Smart Contracts (SCs) and what to look for. More specifically we are going to focus in specific keywords and how to analyse them.  The points analysed are going to be: User supplied input filtering, when interacting directly with SC Interfacing with external SCs Interfacing with DApp applications SC formal verification Wallet authentication in DApp SC Programming Mindset When designing an SC ecosystem (a group of SCs, constitutes an ecosystem) is it wise to have some specific concepts ...

  Elusive Thoughts celebrates 9 years of blogging about hacking  Elusive Thoughts just created its first  non-fungible token (NFT), a digital file whose unique identity and ownership are verified on a blockchain (a digital ledger).  There is a hidden secret in my NFT, please find it. Buy my NFT at  rarible.com  

INTRODUCTION  Ethereum Smart Contracts and other complex blockchain programs are new, promising and highly experimental. Therefore, we should expect constant changes in the security landscape, as new bugs and security risks are discovered, and new best practices are developed [1].  This article is going to focus on threat modeling of smart contract applications. Threat modelling is a process by which threats, such as absence of appropriate safeguards, can be identified, enumerated, and mitigation can be prioritized accordingly. The purpose of threat model is to provide contract applications defenders with a systematic analysis of what controls or defenses need to be included, given the nature of the system, the probable attacker's profile, the most likely attack vectors, and the assets most desired by an attacker.  Smart contract programming requires a different engineering mindset than we may be used to. The cost of failure can be high, and change can be difficult, ...

Introduction This article is going to focus on "Programmable Money Overflow Attacks" on Ethereum and this is the way hackers can become rich and famous. More specifically we are going to discuss the batchOverflow attack. The batchOverflow Bug was identified in multiple ERC20 Smart Contracts [3] (CVE-2018–10299), back in 2018, when Ethereum was relatively new. [1]   The batchOverflow attack is a typical integer overflow attack in the batchTransfer function of a smart contract implementation for the Beauty Ecosystem Coin (BEC). The BEC was an Ethereum ERC20 compliant token that allowed attackers to accomplish an unauthorized increase of digital assets by providing two _receivers arguments in conjunction with a large _value argument, as exploited in the wild in April 2018 [2]. But before we move into replicating the attack, it is better if we explain a few Blockchain properties. The Code Is Law Principle   The "code is law principle" is the principle that no...