I would highly recommend anyone interested in pentesting smart contracts look at the work Trail of Bits has been putting out: https://blog.trailofbits.com/?s=smart+contract&submit=Search

Start with "246 Findings From our Smart Contract Audits: An Executive Summary" [1]

[1] https://blog.trailofbits.com/2019/08/08/246-findings-from-ou...