  The rapid growth in popularity and hype surrounding digital assets such as
art, video, and music in the form of non-fungible tokens (NFTs) has made them a
lucrative investment opportunity, with NFT-based sales surpassing $25B in 2021
alone. However, the volatility and general lack of technical understanding of
the NFT ecosystem have led to the spread of various scams. The success of an
NFT heavily depends on its online virality. As a result, creators use dedicated
promotion services to drive engagement to their projects on social media
websites, such as Twitter. However, these services are also utilized by
scammers to promote fraudulent projects that attempt to steal users'
cryptocurrency assets, thus posing a major threat to the ecosystem of NFT
sales.
  In this paper, we conduct a longitudinal study of 439 promotion services
(accounts) on Twitter that have collectively promoted 823 unique NFT projects
through giveaway competitions over a period of two months. Our findings reveal
that more than 36% of these projects were fraudulent, comprising of phishing,
rug pull, and pre-mint scams. We also found that a majority of accounts
engaging with these promotions (including those for fraudulent NFT projects)
are bots that artificially inflate the popularity of the fraudulent NFT
collections by increasing their likes, followers, and retweet counts. This
manipulation results in significant engagement from real users, who then invest
in these scams. We also identify several shortcomings in existing anti-scam
measures, such as blocklists, browser protection tools, and domain hosting
services, in detecting NFT-based scams. We utilized our findings to develop a
machine learning classifier tool that was able to proactively detect 382 new
fraudulent NFT projects on Twitter.
