PancakeSwap Lottery Bug Fixed - Revision history

Azoundria at 23:48, 2 May 2023

2023-05-02T23:48:42Z

← Older revision		Revision as of 17:48, 2 May 2023
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	{{Imported Case Study\|source=https://www.quadrigainitiative.com/casestudy/pancakeswaplotterybugfixed.php}}		{{Imported Case Study 2\|source=https://www.quadrigainitiative.com/casestudy/pancakeswaplotterybugfixed.php}}
	{{Unattributed ~~Citations~~}}		{{Unattributed Sources}}

	[[File:Pancakeswap.jpg\|thumb\|PancakeSwap]]The PancakeSwap smart contract included a lottery. While the lottery was not actively running, the smart contract was still live and there were still $700k sitting in a smart contract hot wallet.		[[File:Pancakeswap.jpg\|thumb\|PancakeSwap]]The PancakeSwap smart contract included a lottery. While the lottery was not actively running, the smart contract was still live and there were still $700k sitting in a smart contract hot wallet.
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	Due to having a bug bounty program, a white hat hacker uncovered the issue and claimed the reward. The contract funds were withdrawn before they could be stolen.		Due to having a bug bounty program, a white hat hacker uncovered the issue and claimed the reward. The contract funds were withdrawn before they could be stolen.

	This is a global/international case not involving a specific country.		This is a global/international case not involving a specific country.<ref name="blockthreat-2673" /><ref name="immunefimedium-2795" /><ref name="junorousetwitter-2796" /><ref name="binancechainnews-2457" /><ref name="bscscan-2797" /><ref name="bscscan-2798" /><ref name="bscscan-2799" /><ref name="junorousetwitter-2800" />
	<ref name="blockthreat-2673" /><ref name="immunefimedium-2795" /><ref name="junorousetwitter-2796" /><ref name="binancechainnews-2457" /><ref name="bscscan-2797" /><ref name="bscscan-2798" /><ref name="bscscan-2799" /><ref name="junorousetwitter-2800" />

	== About PancakeSwap ==		== About PancakeSwap ==
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	!Description		!Description
	\|-		\|-
	\|April 27th, 2021 ~~12:00:00 AM~~		\|April 27th, 2021
	\|Main Event		\|Main Event
	\|Expand this into a brief description of what happened and the impact. If multiple lines are necessary, add them here.		\|Expand this into a brief description of what happened and the impact. If multiple lines are necessary, add them here.
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	\|		\|
	\|}		\|}

			== 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 ==		== Total Amount Lost ==
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	== Ongoing Developments ==		== Ongoing Developments ==
	What parts of this case are still remaining to be concluded?		What parts of this case are still remaining to be concluded?
			== General Prevention Policies ==
	== Prevention Policies ==
	There were no losses in this case, due to the bug bounty program.		There were no losses in this case, due to the bug bounty program.

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	Lotteries may also be possible with smart contract insurance.		Lotteries may also be possible with smart contract insurance.
			== 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 ==
	<references><ref name="blockthreat-2673">[https://blockthreat.substack.com/p/blockthreat-week-26-2021 No Title] (Jul 23, 2021)</ref>		<references><ref name="blockthreat-2673">[https://blockthreat.substack.com/p/blockthreat-week-26-2021 No Title] (Jul 24, 2021)</ref>

	<ref name="immunefimedium-2795">[https://medium.com/immunefi/pancakeswap-logic-error-bug-fix-postmortem-f2d02adb6983 Pancakeswap Logic Error Bug Fix Postmortem] (Jul 23, 2021)</ref>		<ref name="immunefimedium-2795">[https://medium.com/immunefi/pancakeswap-logic-error-bug-fix-postmortem-f2d02adb6983 Pancakeswap Logic Error Bug Fix Postmortem] (Jul 24, 2021)</ref>

	<ref name="junorousetwitter-2796">[https://twitter.com/junorouse @junorouse Twitter] (Jul 23, 2021)</ref>		<ref name="junorousetwitter-2796">[https://twitter.com/junorouse @junorouse Twitter] (Jul 24, 2021)</ref>

	<ref name="binancechainnews-2457">[https://binancechain.news/pancakeswap-project-insight-a-dex-amm-and-yield-farming-project/2020/11/17/ PancakeSwap Project Insight: A Dex AMM and Yield Farming Project - Binance Chain News] (Aug 10, 2021)</ref>		<ref name="binancechainnews-2457">[https://binancechain.news/pancakeswap-project-insight-a-dex-amm-and-yield-farming-project/2020/11/17/ PancakeSwap Project Insight: A Dex AMM and Yield Farming Project - Binance Chain News] (Aug 11, 2021)</ref>

	<ref name="bscscan-2797">[https://bscscan.com/tx/0xd2aff5884c3ce47c59931735e43c3e5f17aee18ebc6be0f6bf20f3fca08ccf61 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 29, 2021)</ref>		<ref name="bscscan-2797">[https://bscscan.com/tx/0xd2aff5884c3ce47c59931735e43c3e5f17aee18ebc6be0f6bf20f3fca08ccf61 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 30, 2021)</ref>

	<ref name="bscscan-2798">[https://bscscan.com/tx/0x51b7a60fb98601d6ed96f4cb3bda331936c6631ef65ee0e3e75d85873be98b47 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 29, 2021)</ref>		<ref name="bscscan-2798">[https://bscscan.com/tx/0x51b7a60fb98601d6ed96f4cb3bda331936c6631ef65ee0e3e75d85873be98b47 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 30, 2021)</ref>

	<ref name="bscscan-2799">[https://bscscan.com/tx/0xc6ab649d6801fbafabd59a0cda5c54328c93fb27353055efe6c82aef65fa4633 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 29, 2021)</ref>		<ref name="bscscan-2799">[https://bscscan.com/tx/0xc6ab649d6801fbafabd59a0cda5c54328c93fb27353055efe6c82aef65fa4633 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 30, 2021)</ref>

	<ref name="junorousetwitter-2800">[https://twitter.com/junorouse/status/1387600357878996992 @junorouse Twitter] (Aug 29, 2021)</ref></references>		<ref name="junorousetwitter-2800">[https://twitter.com/junorouse/status/1387600357878996992 @junorouse Twitter] (Aug 30, 2021)</ref></references>

Azoundria at 23:50, 18 February 2023

2023-02-18T23:50:58Z

← Older revision		Revision as of 17:50, 18 February 2023
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	{{Imported Case Study\|source=https://www.quadrigainitiative.com/casestudy/pancakeswaplotterybugfixed.php}}		{{Imported Case Study\|source=https://www.quadrigainitiative.com/casestudy/pancakeswaplotterybugfixed.php}}
			{{Unattributed Citations}}

	[[File:Pancakeswap.jpg\|thumb\|PancakeSwap]]The PancakeSwap smart contract included a lottery. While the lottery was not actively running, the smart contract was still live and there were still $700k sitting in a smart contract hot wallet.		[[File:Pancakeswap.jpg\|thumb\|PancakeSwap]]The PancakeSwap smart contract included a lottery. While the lottery was not actively running, the smart contract was still live and there were still $700k sitting in a smart contract hot wallet.
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	This is a global/international case not involving a specific country.		This is a global/international case not involving a specific country.
			<ref name="blockthreat-2673" /><ref name="immunefimedium-2795" /><ref name="junorousetwitter-2796" /><ref name="binancechainnews-2457" /><ref name="bscscan-2797" /><ref name="bscscan-2798" /><ref name="bscscan-2799" /><ref name="junorousetwitter-2800" />

	== About PancakeSwap ==		== About PancakeSwap ==
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	Don't Include:		Don't Include:

	* Any wording which directly states or implies that the business is/was illegitimate, or that a vulnerability existed.		* 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.		* Anything that wasn't reasonably knowable at the time of the event.
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	\|-		\|-
	\|April 27th, 2021 12:00:00 AM		\|April 27th, 2021 12:00:00 AM
	\|~~First~~ Event		\|Main Event
	\|~~This is an expanded~~ description of what happened and the impact. If multiple lines are necessary, add them here.		\|Expand this into a brief description of what happened and the impact. If multiple lines are necessary, add them here.
	\|-
	\|
	\|
	\|
	\|-		\|-
	\|		\|
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	== Total Amount Lost ==		== Total Amount Lost ==
	The total amount lost ~~is unknown~~.		The total amount lost has been estimated at $700,000 USD.

	How much was lost and how was it calculated? If there are conflicting reports, which are accurate and where does the discrepancy lie?		How much was lost and how was it calculated? If there are conflicting reports, which are accurate and where does the discrepancy lie?
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	== Total Amount Recovered ==		== Total Amount Recovered ==
	~~It is unknown how much was~~ 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?		What funds were recovered? What funds were reimbursed for those affected users?
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	== References ==		== References ==
	[https://blockthreat.substack.com/p/blockthreat-week-26-2021 No Title] (Jul 23)		<references><ref name="blockthreat-2673">[https://blockthreat.substack.com/p/blockthreat-week-26-2021 No Title] (Jul 23, 2021)</ref>

	[https://medium.com/immunefi/pancakeswap-logic-error-bug-fix-postmortem-f2d02adb6983 Pancakeswap Logic Error Bug Fix Postmortem] (Jul 23)		<ref name="immunefimedium-2795">[https://medium.com/immunefi/pancakeswap-logic-error-bug-fix-postmortem-f2d02adb6983 Pancakeswap Logic Error Bug Fix Postmortem] (Jul 23, 2021)</ref>

	[https://twitter.com/junorouse @junorouse Twitter] (Jul 23)		<ref name="junorousetwitter-2796">[https://twitter.com/junorouse @junorouse Twitter] (Jul 23, 2021)</ref>

	[https://binancechain.news/pancakeswap-project-insight-a-dex-amm-and-yield-farming-project/2020/11/17/ PancakeSwap Project Insight: A Dex AMM and Yield Farming Project - Binance Chain News] (Aug 10)		<ref name="binancechainnews-2457">[https://binancechain.news/pancakeswap-project-insight-a-dex-amm-and-yield-farming-project/2020/11/17/ PancakeSwap Project Insight: A Dex AMM and Yield Farming Project - Binance Chain News] (Aug 10, 2021)</ref>

	[https://bscscan.com/tx/0xd2aff5884c3ce47c59931735e43c3e5f17aee18ebc6be0f6bf20f3fca08ccf61 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 29)		<ref name="bscscan-2797">[https://bscscan.com/tx/0xd2aff5884c3ce47c59931735e43c3e5f17aee18ebc6be0f6bf20f3fca08ccf61 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 29, 2021)</ref>

	[https://bscscan.com/tx/0x51b7a60fb98601d6ed96f4cb3bda331936c6631ef65ee0e3e75d85873be98b47 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 29)		<ref name="bscscan-2798">[https://bscscan.com/tx/0x51b7a60fb98601d6ed96f4cb3bda331936c6631ef65ee0e3e75d85873be98b47 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 29, 2021)</ref>

	[https://bscscan.com/tx/0xc6ab649d6801fbafabd59a0cda5c54328c93fb27353055efe6c82aef65fa4633 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 29)		<ref name="bscscan-2799">[https://bscscan.com/tx/0xc6ab649d6801fbafabd59a0cda5c54328c93fb27353055efe6c82aef65fa4633 Binance Transaction Hash (Txhash) Details \| BscScan] (Aug 29, 2021)</ref>

	[https://twitter.com/junorouse/status/1387600357878996992 @junorouse Twitter] (Aug 29)		<ref name="junorousetwitter-2800">[https://twitter.com/junorouse/status/1387600357878996992 @junorouse Twitter] (Aug 29, 2021)</ref></references>

Azoundria: Created page with "{{Imported Case Study|source=https://www.quadrigainitiative.com/casestudy/pancakeswaplotterybugfixed.php}} PancakeSwapThe PancakeSwap smart contract included a lottery. While the lottery was not actively running, the smart contract was still live and there were still $700k sitting in a smart contract hot wallet. Due to having a bug bounty program, a white hat hacker uncovered the issue and claimed the reward. The contract funds were withd..."

2023-01-26T05:42:30Z

Created page with "{{Imported Case Study|source=https://www.quadrigainitiative.com/casestudy/pancakeswaplotterybugfixed.php}} thumb|PancakeSwapThe PancakeSwap smart contract included a lottery. While the lottery was not actively running, the smart contract was still live and there were still $700k sitting in a smart contract hot wallet. Due to having a bug bounty program, a white hat hacker uncovered the issue and claimed the reward. The contract funds were withd..."

New page

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

[[File:Pancakeswap.jpg|thumb|PancakeSwap]]The PancakeSwap smart contract included a lottery. While the lottery was not actively running, the smart contract was still live and there were still $700k sitting in a smart contract hot wallet.

Due to having a bug bounty program, a white hat hacker uncovered the issue and claimed the reward. The contract funds were withdrawn before they could be stolen.

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

== About PancakeSwap ==
"PancakeSwap is a decentralized exchange (DEX) on the Binance Smart Chain (BSC), which uses permission less liquidity pools run by algorithms. This creates what is known as an automated market maker (AMM)."

"Whitehat Juno submitted a critical vulnerability in PancakeSwap’s lottery contract on April 27." "Prior to the reporting of this vulnerability, PancakeSwap had already shut down its lottery contract by disallowing new lottery drawings." "However, even though no additional drawings were held, the contract still had approximately $700,000 in funds remaining because users still had outstanding tickets to claim. The simultaneous existence of the bug and the funds locked up would have made the contract worth exploiting by a malicious user."

"Due to insufficient validation, a malicious user could have claimed the same winning ticket at least 255 times in a single transaction, meaning the reward size was 255 times too great. A total of $700,000 in funds could have been lost, had the vulnerability been exploited."

"An analysis of this code block reveals that if a ticket is submitted to multiClaim multiple times (that is, the _tickets[] aren’t all unique), the duplicate ticket will be able to be redeemed multiple times. This happens because Lottery.sol checks that the ticket hasn’t been claimed, and it checks all the tickets before marking any of them as claimed. Additionally, LotteryNFT.sol multiClaimReward doesn’t require that the ticket being claimed hasn’t already been marked as claimed."

"None of the checks account for the possibility that a malicious user would pass the same ticket multiple times. The result is that the total reward is a function of the reward itself multiplied by the number of times the ticket is claimed."

"Step 1: Buy a lottery ticket. Step 2: Win the lottery. The lottery works by allowing you to pick a number between 1 and 14, and you pick four numbers. There are prizes available for matching at least two of the numbers together. If you match four numbers together, you win the grand prize. However, the exploit does not depend on winning the grand prize. The exploit depends on winning at least some amount of money, which is not difficult. Step 3: Submit the malicious transaction, which calls multiClaim(), and pass the winning ticket 255 times, where each ticket is the ID of the NFT lottery ticket. There’s no validation that a user is claiming the same ticket, so that user can effectively claim the same ticket an unlimited number of tickets — with the only limit being the blocksize of the transaction."

"PancakeSwap fixed [the] logic bug after it was responsibly disclosed by Juno." "Immunefi began the process of disclosure assistance, contacting every project on Binance Smart Chain that had forked PancakeSwap’s lottery contract to inform them of the vulnerability as well. ApeSwap, PantherSwap, and Knights DeFi were vulnerable. All three decided to pay a bounty to the whitehat as well."

"PancakeSwap paid $70,000 in CAKE tokens. ApeSwap paid $2,700. PantherSwap paid 10,290 PANTHER tokens. Knights DeFi paid 7,000 KNIGHT tokens. All affected projects have fixed the vulnerability."

"After Juno reported the vulnerability through Immunefi, PancakeSwap withdrew all funds out of the contract." "PantherSwap, however, kept the lottery contract active and applied a fix as suggested by Immunefi’s CTO Duncan Townsend. The fix was to rewrite the multiClaim() function." "ApeSwap shut down its lottery contract. Knights DeFi took down the contract and migrated to a new one."

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 - PancakeSwap Lottery Bug Fixed
!Date
!Event
!Description
|-
|April 27th, 2021 12:00:00 AM
|First Event
|This is an expanded description of what happened and the impact. If multiple lines are necessary, add them here.
|-
|
|
|
|-
|
|
|
|}

== Total Amount Lost ==
The total amount lost is unknown.

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 ==
It is unknown how much was recovered.

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?

== Prevention Policies ==
There were no losses in this case, due to the bug bounty program.

The lottery would have been more secure if the funds were in an offline multi-signature wallet. The drawing could still be run through the blockchain for process transparency.

Lotteries may also be possible with smart contract insurance.

== References ==
[https://blockthreat.substack.com/p/blockthreat-week-26-2021 No Title] (Jul 23)

[https://medium.com/immunefi/pancakeswap-logic-error-bug-fix-postmortem-f2d02adb6983 Pancakeswap Logic Error Bug Fix Postmortem] (Jul 23)

[https://twitter.com/junorouse @junorouse Twitter] (Jul 23)

[https://binancechain.news/pancakeswap-project-insight-a-dex-amm-and-yield-farming-project/2020/11/17/ PancakeSwap Project Insight: A Dex AMM and Yield Farming Project - Binance Chain News] (Aug 10)

[https://bscscan.com/tx/0xd2aff5884c3ce47c59931735e43c3e5f17aee18ebc6be0f6bf20f3fca08ccf61 Binance Transaction Hash (Txhash) Details | BscScan] (Aug 29)

[https://bscscan.com/tx/0x51b7a60fb98601d6ed96f4cb3bda331936c6631ef65ee0e3e75d85873be98b47 Binance Transaction Hash (Txhash) Details | BscScan] (Aug 29)

[https://bscscan.com/tx/0xc6ab649d6801fbafabd59a0cda5c54328c93fb27353055efe6c82aef65fa4633 Binance Transaction Hash (Txhash) Details | BscScan] (Aug 29)

[https://twitter.com/junorouse/status/1387600357878996992 @junorouse Twitter] (Aug 29)