https://www.bleepingcomputer.com/news/security/researchers-last-year-s-icos-had-five-security-vulnerabilities-on-average/ :
Security researchers have found, on average, five security flaws in each cryptocurrency ICO (Initial Coin Offering) held last year. Only one ICO held in 2017 did not contain any critical flaws.
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A previous study also found that 81% of recent ICOs were scams, which might explain why most ICO organizers didn't bother with security.