What happened with the UNI/USDT trading pair on Uniswap?

[JeromeTash]

Since I am not a user of Uniswap, I am a little unfamiliar with this situation.

The UNI/USDT price was weird at some point, costing roughly $644 per token according to dextools. What is going on? Is it a case of market manipulation, accidental buying and selling, or some sort of scam?
https://www.dextools.io/app/en/ether/pair-explorer/0x5ac13261c181a9c3938bfe1b649e65d10f98566b

[dbshck]

Not 100% sure but it looks like an MEV bot (0x00..8987) doing a sandwich attack. The victim is transaction #2, that trx paid $63k/UNI and lost about $50 USDT. Here's how it works:

• The attacker (0x00..8987) frontran trx#2 by buying nearly all UNI available in the UNI/USDT V2 pool (578.919). Now the pool has very little UNI and lots of USDT, essentially inflating the UNI price.
• The victim (0x52..22c1) make a swap of 51 USDT for only 0.0312 UNI
• The attacker backrun the transaction, i.e., selling all of their UNI bought from trx#1 in the same pool for 373,252 USDT

From this sandwich attack, the attacker gained 28 USDT and paid around $25 in ETH for gas, making only $3 net profit. Yeah these MEV bots are crazy.

[JeromeTash]

snip

Quite interesting, thanks for the info mate. I will look it up, it will be worth reading

I noticed that it happened again a few hours ago and one striking thing is the middle transaction, the one we think is the victim, always has the same values (the price in USD, Amount in UNI, Total USDT etc) just like the previous incident. Something is definitely up