ERC-20 fees are permanently locked in Treasury — frozen funds

Source & credit. Reproduction of a public audit finding curated by AuditVault — the original finding: 57056-erc-20-tokens-cannot-be-withdrawn-from-treasury-contract-tra. Standalone Foundry PoC and full write-up: 57056-erc-20-tokens-cannot-be-withdrawn-from-treasury-contract-tra_exp in the evm-hack-registry mirror.

Vulnerability classes: vuln/dos/frozen-funds · vuln/logic/missing-check

Reproduction: self-contained synthetic Foundry reduction; see output.txt.

Key info#

Field	Value
Loss	ERC-20 fee balances sent to Treasury cannot be recovered
Vulnerable contract	`Treasury.withdraw` (ETH-only)
Attacker EOA	`0x1111111111111111111111111111111111111111`
Attack contract	`FeeToken` and `Treasury` via `Exploit`
Attack tx	`Exploit.run()`
Chain / block / date	Ethereum model · block 0 · 2025-03
Compiler	`solc 0.8.24` (synthetic)
Bug class	Missing ERC-20 withdrawal path

TL;DR#

The Treasury exposes a native-ETH withdrawal only. ERC-20 fee tokens accumulate at the contract and the attempted token recovery selector reverts, leaving the balance frozen.

Background#

Otim accepts registered ERC-20 fee tokens but the reviewed Treasury implementation only checks address(this).balance. This reduction models the asset-flow mismatch.

The vulnerable code#

SOLIDITY

function withdraw(address target, uint256 value) external {
    (bool ok,) = payable(target).call{value: value}(""); // ETH only
    require(ok);
}

Root cause#

The contract has no owner-authorized IERC20(token).transfer recovery function, so token balances are not part of the withdrawal design.

Preconditions#

Users pay fees with an ERC-20 accepted by the protocol.
The token is transferred to Treasury.

Attack walkthrough#

Exploit mints 1,000 fee tokens to Treasury.
It calls the absent withdrawToken selector.
The Proof event at output.txt:373 shows all 1,000 tokens remain locked.

Diagrams#

flowchart LR U[Fee payer] --> T[Treasury ERC-20 balance] T --> X[ETH-only withdraw] X --> L[Token remains frozen]

Remediation#

Add an owner-authorized, checked ERC-20 withdrawal that rejects zero targets and emits an event; cover every supported fee asset with recovery tests.

How to reproduce#

BASH

cd evm-hack-registry/57056-erc-20-tokens-cannot-be-withdrawn-from-treasury-contract-tra_exp
forge test -vvvvv

Sources#

Reference: https://github.com/trailofbits/publications/blob/master/reviews/2025-03-otim-smart-wallet-securityreview.pdf

Sources & further analysis#

Reproductions & code

Standalone PoC + full trace: 57056-erc-20-tokens-cannot-be-withdrawn-from-treasury-contract-tra_exp (evm-hack-registry mirror).
AuditVault finding: 57056-erc-20-tokens-cannot-be-withdrawn-from-treasury-contract-tra.

Alerts & third-party analyses

Web3Sec X hacked database: search.
Rekt leaderboard: search.
Solodit incident search: search.

These dashboards index community alerts tweets, post-mortems, and independent write-ups. Reach them through the protocol name above to cross-check this reproduction against other analyses.

Source-level debugger — step opcodes and Solidity in sync