Polymarket, Judao, Hyperbridge: A Key Compromise, a Sell Logic Flaw, and a Missing Bounds Check
Three exploits this week, and the lesson sits in the difference between them.
One was a compromised key, a reminder that security reaches beyond the contract itself. The other two were code-level bugs sitting in plain sight, the kind that surface when you test for them before you ship. That is $470K that never had to leave the building.
In Brief
Polymarket lost $700K due to a compromised private key.
Judao lost $228K due to a sell logic flaw that enabled price manipulation.
Hyperbridge lost $242K due to a missing bounds check.
Hacks Analysis
Polymarket | Amount Lost: $700K
On May 21st, the Polymarket exploit on Polygon resulted in a $700K loss. The root cause of the exploit was a private key compromise affecting a wallet used for internal operations. The attacker gained access to the key and used it to execute unauthorized transfers of POL tokens. The Polymarket team confirmed that the exploit did not involve a smart contract vulnerability and they began rotating backend keys.
One of Many Transactions (on Polygon): 0x9faf63d96cab3ca02680452a4c66bdf7ae8a2901307ec27a180da47d96ef2dc7
Judao | Amount Lost: $228K
On April 28th, the Judao exploit on the BSC resulted in a $228K loss. The root cause of the exploit was a flaw in the token’s sell logic (in _update() function) that allowed the liquidity pool reserves to be modified during a swap. When the attacker sold JUDAO tokens, the contract burned tokens from the pool and called sync() before the swap output was calculated. This caused the pool to calculate fewer JUDAO tokens in circulation, artificially increasing the token price. The attacker used a $2.3M USDT flash loan to purchase 5.5M JUDAO, then sold the tokens back into the manipulated pool to make a profit.
Exploited Contract (on BSC): 0xf55DFF7898930a2D28cDbC39D615b1624ac86888
On April 13th, the Hyperbridge exploit on the Ethereum mainnet resulted in a $242K loss. The root cause of the exploit was a missing bounds check on leaf_index in the handlePostRequests() function. The function accepted any arbitrary leaf_index and passed it to the MMR proof verifier without verifying that it was smaller than leafCount. The attacker submitted an out-of-bounds index and bypassed proof verification to get minting permissions. The attacker then minted bridged tokens, and sold them for profit.
The rich text element allows you to create and format headings, paragraphs, blockquotes, images, and video all in one place instead of having to add and format them individually. Just double-click and easily create content.
A rich text element can be used with static or dynamic content. For static content, just drop it into any page and begin editing. For dynamic content, add a rich text field to any collection and then connect a rich text element to that field in the settings panel. Voila!
Headings, paragraphs, blockquotes, figures, images, and figure captions can all be styled after a class is added to the rich text element using the "When inside of" nested selector system.
Follow-up: Conduct a follow-up review to ensure that the remediation steps were effective and that the smart contract is now secure.
Follow-up: Conduct a follow-up review to ensure that the remediation steps were effective and that the smart contract is now secure.
In Brief
Remitano suffered a $2.7M loss due to a private key compromise.
GAMBL’s recommendation system was exploited.
DAppSocial lost $530K due to a logic vulnerability.
Rocketswap’s private keys were inadvertently deployed on the server.
Hacks
Hacks Analysis
Huobi | Amount Lost: $8M
On September 24th, the Huobi Global exploit on the Ethereum Mainnet resulted in a $8 million loss due to the compromise of private keys. The attacker executed the attack in a single transaction by sending 4,999 ETH to a malicious contract. The attacker then created a second malicious contract and transferred 1,001 ETH to this new contract. Huobi has since confirmed that they have identified the attacker and has extended an offer of a 5% white hat bounty reward if the funds are returned to the exchange.
