How Lendf.Me was close to lose $25m worth of cryptocurrency

Aina Lucien Razafindraibe
2 min readApr 28, 2020
Photo by Clifford Photography on Unsplash

Lendf.Me is an online lending platform based on Etherum.

If you are new to cryptocurrency, Etherum allows you to buy and sell online without any third party. It is decentralized meaning that it is beyond the control of any given country. Besides, its users are granted more control over the data. In fact, every transaction is controlled by what is called « miners ».

Concerns about security

It is often said cryptocurrency is the future of finance. Still, it hasn’t seen any mass adoption. The reason may root from its security perception. And the case of’ s attack will reinforce that negative image. Etherum asserts that this bug per se was not intrinsically related to its platform but to the so-called « imBTC token ». This is maybe true but making these differences requires some technical knowledge that the final audiences lack ( layman). This is why cryptocurrency still struggle. Nonetheless, let’s try to understand how managed to lose this astonishing amount.

« Reentrancy »

In a nutshell, the attackers managed to avoid control by making the transaction before it is accepted or declined. And multiple times. You get it? No, ok. Let’s put it simply: the transactions happened first, then after that we check if it was appropriate or not. And the attacker just changed the code so that it avoids this control. Hopefully for, the attackers return the fund since they somehow exposed their IP addresses accidentally.



Aina Lucien Razafindraibe

Entrepreneur. Founder of Bootcamp Fullstack Tana.@Ivatois on twitter