Azoundria: Created page with "{{Imported Case Study|source=https://www.quadrigainitiative.com/casestudy/bunkerfinancefunctionparametervulnerability.php}} {{Unattributed Sources}} Bunker Finance Logo/HomepageBunker Finance is an NFT borrowing protocol, which allows users to borrow funds against their NFTs, or to lend funds and earn interest. On April 15th, 2022, the protocol was provided with details of an exploit, which would have allowed users of the protocol to ste..."

2024-04-08T22:41:43Z

Created page with "{{Imported Case Study|source=https://www.quadrigainitiative.com/casestudy/bunkerfinancefunctionparametervulnerability.php}} {{Unattributed Sources}} thumb|Bunker Finance Logo/HomepageBunker Finance is an NFT borrowing protocol, which allows users to borrow funds against their NFTs, or to lend funds and earn interest. On April 15th, 2022, the protocol was provided with details of an exploit, which would have allowed users of the protocol to ste..."

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{{Imported Case Study|source=https://www.quadrigainitiative.com/casestudy/bunkerfinancefunctionparametervulnerability.php}}
{{Unattributed Sources}}

[[File:Bunkerfinance.jpg|thumb|Bunker Finance Logo/Homepage]]Bunker Finance is an NFT borrowing protocol, which allows users to borrow funds against their NFTs, or to lend funds and earn interest. On April 15th, 2022, the protocol was provided with details of an exploit, which would have allowed users of the protocol to steal NFTs provided as collateral by other users. The vulnerability required the user to provide their NFT as collateral with an incorrect count of tokens provided, then sell or transfer the NFT to another user who also provided the same NFT as collateral. Deposits of NFTs were temporarily suspended while the issue was resolved. shunwilly was ultimately provided with an undisclosed bounty amount.

This is a global/international case not involving a specific country.<ref name="newsletter-13117" /><ref name="bunkerfinancemedium-13253" /><ref name="bunkerfinance-13254" /><ref name="bunkerfinancetwitter-13255" /><ref name="bunkerfinance-13256" /><ref name="bunkerfinance-13257" />

== About Bunker Finance ==
"Get a loan using your NFTs Bunker is the easiest way to borrow against your NFTs" "bunker.finance allows you to instantly lend and borrow without needing to wait to match borrowers and lenders. Our protocol currently allows you to borrow against CryptoPunks but more NFT collections will soon become available to use as collateral."

"Each NFT collection has its own, separate lending market on Bunker." "Borrow as much as you need and repay whenever you like." "As a lender, you earn interest every single block, and can withdraw your capital at any time." "We allow borrowers to take out loans instantly and enable lenders to immediately start earning interest. Borrowers no longer need to wait to be matched manually to a lender and vice versa."

"Bunker is a platform for NFT-backed loans. As a borrower, you can use any supported NFT as collateral for a loan of ETH or ERC-20 tokens. As a lender, you can deposit ETH or ERC-20 tokens into a lending pool for any supported NFT collection and immediately start earning interest."

"NFTs deposited to Bunker are represented as bNFTs. To mint a bNFT, visit the pools page, and select the appropriate pool. You should see all of your NFTs belonging to the specified collection in the ‘Collateral’ section. Simply click on the ‘Wrap’ button to wrap your NFT as a bNFT. While a bNFT is being used as collateral for a loan, it cannot be transferred from your wallet until the loan is fully repaid. When the bNFT is not actively being used as collateral, it is freely transferable."

"Bunker Finance patched a function parameter validation vulnerability in its CryptoPunks lending pool thanks to a responsible disclosure by shenwilly."

"When depositing NFTs as collateral on Bunker, users receive bNFTs (referred to internally as cNFTs). The cNFT contract is an ERC-1155 compliant wrapper that stores an underlying ERC-1155, ERC-721, or CryptoPunk and enables it to be used as collateral on Bunker.

When minting cNFTs with ERC721 or Punks, the param amounts is not checked. Anyone can input a large value and that amount of CNft will be minted to them. They can then redeem the NFT, while still having leftover CNfts corresponding to that NFT. This means that when the NFT has changed hands and gets deposited into CNft again, the attacker can redeem it again and steal the NFT."

"Attacker calls mint, using their punkId as tokenId and 5 as the amount. Attacker receives 5 CNfts. Attacker calls redeem to retrieve their punk. Left with 4 CNfts. Attacker sells the punk to Alice. Alice calls mint using the same punk. Attacker can now redeem the punk, stealing it from Alice."

"The mint function of CNft as well as the seize and redeem functions have all been updated to check that amounts has not incorrectly specified. For all non-ERC1155s, amounts can now only be 1. These updates will be included in v2 of our protocol, which will be going live shortly. In the mean time, depositing collateral on v1 remains paused but assets can be withdrawn at any time."

"As a result, no assets were lost as a result of the vulnerability and a fix has been included in our upcoming v2 release. Details of our upcoming audit contest and bug bounty program will be published soon. In the meantime, please reach out to us via Discord for any vulnerability disclosures."

"We would like to thank @shenwilly_ again, as well as our security team for responding quickly and preventing any losses."

This is a global/international case not involving a specific country.

The background of the exchange platform, service, or individuals involved, as it would have been seen or understood at the time of the events.

Include:

* Known history of when and how the service was started.
* What problems does the company or service claim to solve?
* What marketing materials were used by the firm or business?
* Audits performed, and excerpts that may have been included.
* Business registration documents shown (fake or legitimate).
* How were people recruited to participate?
* Public warnings and announcements prior to the event.

Don't Include:
* Any wording which directly states or implies that the business is/was illegitimate, or that a vulnerability existed.
* Anything that wasn't reasonably knowable at the time of the event.
There could be more than one section here. If the same platform is involved with multiple incidents, then it can be linked to a main article page.

== The Reality ==
This sections is included if a case involved deception or information that was unknown at the time. Examples include:

* When the service was actually started (if different than the "official story").
* Who actually ran a service and their own personal history.
* How the service was structured behind the scenes. (For example, there was no "trading bot".)
* Details of what audits reported and how vulnerabilities were missed during auditing.

== What Happened ==
The specific events of the loss and how it came about. What actually happened to cause the loss and some of the events leading up to it.
{| class="wikitable"
|+Key Event Timeline - Bunker Finance Function Parameter Vulnerability
!Date
!Event
!Description
|-
|April 15th, 2022 8:36:00 PM MDT
|Announced Pause
|The Bunker Finance team announces that depositing collateral on the CryptoPunks pool is temporarily paused while they investigate a vulnerability. "Your deposited punks and supplied funds are safe and can be withdrawn at any time."
|-
|April 25th, 2022 6:36:59 PM MDT
|Medium Article
|A medium article is published on the responsible disclosure.
|}

== Technical Details ==
This section includes specific detailed technical analysis of any security breaches which happened. What specific software vulnerabilities contributed to the problem and how were they exploited?

== Total Amount Lost ==
No funds were lost.

How much was lost and how was it calculated? If there are conflicting reports, which are accurate and where does the discrepancy lie?

== Immediate Reactions ==
How did the various parties involved (firm, platform, management, and/or affected individual(s)) deal with the events? Were services shut down? Were announcements made? Were groups formed?

== Ultimate Outcome ==
What was the end result? Was any investigation done? Were any individuals prosecuted? Was there a lawsuit? Was any tracing done?

== Total Amount Recovered ==
There do not appear to have been any funds recovered in this case.

What funds were recovered? What funds were reimbursed for those affected users?

== Ongoing Developments ==
What parts of this case are still remaining to be concluded?
== Individual Prevention Policies ==
{{Prevention:Individuals:Placeholder}}

{{Prevention:Individuals:End}}

== Platform Prevention Policies ==
{{Prevention:Platforms:Placeholder}}

{{Prevention:Platforms:End}}

== Regulatory Prevention Policies ==
{{Prevention:Regulators:Placeholder}}

{{Prevention:Regulators:End}}

== References ==
<references><ref name="newsletter-13117">[https://newsletter.blockthreat.io/p/blockthreat-week-25-2022 BlockThreat - Week 25, 2022 - by Peter Kacherginsky] (Mar 18, 2024)</ref>

<ref name="bunkerfinancemedium-13253">[https://medium.com/@bunker_finance/bunker-finance-vulnerability-postmorterm-bnft-amount-manipulation-540ecce6e6e2 Bunker.finance Vulnerability Postmortem — BNft Amount Manipulation | by bunker.finance | Medium] (Apr 8, 2024)</ref>

<ref name="bunkerfinance-13254">[https://bunker.finance/ https://bunker.finance/] (Apr 8, 2024)</ref>

<ref name="bunkerfinancetwitter-13255">[https://twitter.com/bunker_finance/status/1515157253829013504 @bunker_finance Twitter] (Apr 8, 2024)</ref>

<ref name="bunkerfinance-13256">[https://bunker.finance/docs https://bunker.finance/docs] (Apr 8, 2024)</ref>

<ref name="bunkerfinance-13257">[https://bunker.finance/docs/overview/wrapping-and-unwrapping-bNFTs https://bunker.finance/docs/overview/wrapping-and-unwrapping-bNFTs] (Apr 8, 2024)</ref></references>

Bunker Finance Function Parameter Vulnerability - Revision history