By Elizabeth Howcroft LONDON (Reuters) – A bug in the largest NFT marketplace, OpenSea, allowed attackers to purchase at least $1 million worth of NFTs across multiple different wallets for significantly below market price, blockchain analytics firm Elliptic said on Monday. A non-fungible token (NFT) is a form of crypto asset, which records the ownership status of digital files on blockchain. OpenSea is the largest marketplace for speculators and enthusiasts to trade their NFTs, with $4.8 billion worth of sales volume so far in January. But a flaw in the marketplace allowed users to buy certai…