1. One of the most well-known instances of a design flaw attack occurred on Augur. It is a decentralized prediction protocol operating on the Ethereum network. In many prediction markets on Augur, they heavily rely on oracles to provide external information on which bets are placed. Consequently, these markets deceived users into betting on contracts with ambiguous parameters, which ultimately led to disputes and losses.

2.  Design flaw attacks specifically target the oracles and price feeds of protocols within the DeFi space. In this particular scenario, an attacker with malicious intent deliberately deploys a design flaw bug within a marketplace that depends on a single API as its price data source. Subsequently, the API is disabled before expiration. This allows the attacker to manipulate assets, smart contracts, or protocols that depend on the API for their own advantage.

Design flaw attacks can be more difficult to defend against than attacks that target specific vulnerabilities in code or implementation. This is because the underlying design or architecture of a system is often more complex and difficult to change than individual pieces of code. In addition, design flaws can sometimes be difficult to identify or address, especially if they are deeply embedded in the system's architecture.

To defend against design flaw attacks, organizations should :

1. Adopt a security-by-design approach to software development, which involves considering security from the very beginning of the design process. This includes conducting thorough security assessments and testing throughout the development lifecycle, as well as regularly reviewing and updating the design and architecture of systems to identify and address potential vulnerabilities.

 2. Organizations should implement strong access controls and authentication mechanisms to limit the impact of any successful attacks.