What Is a Sandwich Attack in Crypto and How to Protect Against It

Decentralized exchanges (DEXs) offer crypto traders numerous opportunities and distinct advantages. At the same time, these platforms often attract malicious actors intent on causing harm and deriving profit at the expense of unsuspecting fellow traders. While rug pulls and flash loan attacks are often mentioned when discussing the unique threats on decentralized trading platforms, another type of malicious attack — a sandwich attack — gets far less attention.

In the most standard form of sandwich attack, a trader with sinister motives identifies a pending swap transaction on a blockchain and places two orders — one before and one after the targeted transaction — to manipulate the asset price. The culprit's goal is to buy the asset before the expected price increase, and then quickly sell it after the price inflation. The victim of the attack ends up purchasing the asset at the inflated price and then watches helplessly as its price plummets afterward.

Sandwich attacks — while less publicized than some other security vulnerabilities in the world of decentralized finance (DeFi) — can still be devastating for traders who fall victim to these exploits. A trader unaware of being targeted by such an attack may quickly lose significant funds and get wiped out, especially if they actively place orders during the attack phase. 

The good news is that there are several measures that traders can implement to minimize the probability of becoming “filling” for the attacker's breakfast sandwich. In this article, we’re taking a closer look at sandwich attacks, their two main varieties and the key ways to avoid them.

Key Takeaways: