platform: X format: thread (7 tweets) hook: A fresh address claimed 3 years of staking rewards yesterday. Here's the $150K bug that every ERC2771 integration needs to check for. proof: On-chain attack flow, code-level sender identity mismatch, fee accounting bug, LayerZero exit path hashtags: #DeFiSecurity #SmartContractAudit #ERC2771 #ExploitAnalysis #Ethereum #Web3Security review-notes: All data from public sources. Defensive framing only. No weaponization. Verify Crypto Times reporting is accurate.
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1/7 (Hook)
A fresh address claimed 3 years of staking rewards yesterday.
It had never staked a single token.
DBXen lost $150K because of one inconsistency in how it resolves msg.sender. Here's the full attack chain. 🧵
2/7 (The Bug)
DBXen uses ERC2771 meta-transactions with a permissionless forwarder.
The problem: burnBatch() uses _msgSender() correctly.
But onTokenBurned() (the callback) references the forwarder address instead of the actual user.
Two functions. Two different answers to "who called this?"
3/7 (The Exploit)
Attacker creates a fresh wallet.
Calls burnBatch(5560) through the permissionless forwarder.
The callback sees the forwarder address as a "new user." The system backdates it to cycle 0.
That's 1,085 cycles of accumulated fee income. Three years of rewards for zero days of staking.
4/7 (The Payout)
65.28 ETH drained from the fee pool. 2,305 DXN tokens minted. Funds bridged via LayerZero within minutes.
Total damage: ~$150,000.
The entire attack fits in one transaction.
5/7 (Why Scanners Miss This)
Run Slither on this contract. Run Aderyn. Run any static analyzer.
You'll get zero findings for this bug.
Why? It's not a Solidity-level vulnerability. No reentrancy. No overflow. No unchecked call.
It's a business logic flaw that requires understanding how reward math interacts with sender identity across function boundaries.
6/7 (The Pattern)
This is the third economic logic exploit in two weeks:
Static analyzers catch syntax errors. These bugs are design flaws.
7/7 (Prevention + CTA)
If your protocol uses ERC2771:
1. Audit sender resolution across every function boundary
2. Never mix _msgSender() with raw msg.sender
3. Restrict forwarders to whitelisted addresses
4. Validate that new addresses cannot claim historical rewards
The fix is consistency. The lesson is that meta-transaction integrations need specialized review.
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CTA: If your protocol uses ERC2771, audit sender identity resolution today. Reply with questions.