Submitted by camden, also found by cccz, cmichel, danb, defsec, harleythedog, hyh, kenzo, leastwood, palina, pauliax, pmerkleplant, Ruhum, WatchPug, and ye0lde
In short, the NonUSTStrategy is vulnerable to attacks by flash loans on curve pools.
Heres an outline of the attack:
Here is my proof of concept:
https://gist.github.com/CamdenClark/932d5fbeecb963d0917cb1321f754132
I can provide a full forge repo. Just ping me on discord.
Exploiting this line: https://github.com/code-423n4/2022-01-sandclock/blob/a90ad3824955327597be00bb0bd183a9c228a4fb/sandclock/contracts/strategy/NonUSTStrategy.sol#L135
Forge
Use an oracle
naps62 (Sandclock) confirmed 
