---
# System prepended metadata

title: CertiK Client Feedback from Deerfi
tags: [audit-feedback]

---

---

title: CertiK Client Feedback from Deerfi

tags : audit-feedback

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CertiK Client Feedback from Deerfi
===

<!-- Client Feedback Form should be submitted for every **formal** discussion with clients. Use 10 mins to finish it and push to the project git repo through the hackmd embeded plugin: https://hackmd.io/c/tutorials/%2Fs%2Flink-with-github -->

###### tags: `Feedback` `Audit`

:::info
<!-- Participator should include all names of BDs, Engineers who join the discussion -->
- **Client:** Deerfi
- **Date:** Nov 11, 2020
- **Participator:** buyun.xu@certik.com, guilong.li@certik.com
- **Reference:** - [Last week meeting minute](/s/template-meeting-note)
:::

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:mag: Discussion Findings
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<!-- List all discuss topics in the meeting that you think worthy note in the process of the audit. Not necessarily list here all vulnerabilities found in the project. List -->


| Index |Type| Issue Description| Client's Feedbacks | Auditor's Comments | Solved? | Solution |
| ------------- | ------- | ------------ | -------------  | -------- | -------- | -------- |
| 1     | Concerns from our client | Client requested to analyze a relative [news](https://peckshield.medium.com/cheese-bank-incident-root-cause-analysis-d076bf87a1e7) | Client worried about whether their project was vulnerable with flash loan attacks |Deerfi should not have this issue, detailed analysis see below | Y |  |


:closed_book:  Comments 
--
News
https://peckshield.medium.com/cheese-bank-incident-root-cause-analysis-d076bf87a1e7
Cheesebank.io is attacked by flash loan attack, and lost 3,3 million dollars.
Client worried about whether their project was vulnerable with flash loan attacks regarding on above news.

Answer:
Deerfi is a fork of Compound plus the chainlink price oracle.
Compound was audited by Zeppelin. Chainklink is a mainstream price oracle now. Both projects do not encounter this issue.
The issue is with the project Cheesebank.io itself.
The crucial step in this incident is the Cheese Bank uses the amount of WETH in a liquidity pool to estimate the price of the corresponding LP token. 


