Non-payable batch sender blocks result submissions — AuditVault synthetic reduction

Source & credit. Reproduction of a public audit finding curated by AuditVault — the original finding: 55233-h-6-attacker-can-exploits-batch-sender-role-to-block-result. Standalone Foundry PoC and full write-up: 55233-h-6-attacker-can-exploits-batch-sender-role-to-block-result_exp in the evm-hack-registry mirror.

Vulnerability classes: vuln/dos/frozen-funds · vuln/dependency/unchecked-return-value

Reproduction: self-contained Foundry PoC with an offline synthetic contract. Full trace: output.txt.

AuditVault finding: 55233 · H-6: Attacker can exploits batch sender role to block result Submissions via fee transfer reversion

Key info#


Impact	HIGH — Non-payable batch sender blocks result submissions
Protocol	[[SEDA]] Protocol
Finding	AuditVault #55233
Report	https://github.com/sherlock-audit/2024-12-seda-protocol-judging
Source	AuditVault finding
Compiler	`^0.8.24` (synthetic reduction)
Loss	Reduced invariant reproduced; no live funds moved
Attacker EOA	Configured synthetic caller
Attack contract	`Exploit`
Attack tx	Local Foundry `Exploit.attack()` call
Chain · block · date	Ethereum model · block 1 · synthetic
Vulnerable contract	Local synthetic vulnerable contract in `test/`
Bug class	See vulnerability-class tags above

TL;DR#

This bug report discusses an issue with the SEDA protocol that allows an attacker to exploit the batch sender role and block result submissions by using a contract that reverts when receiving native tokens. The root cause of this issue is that the postBatch function allows any address to submit a batch as long as certain conditions are met. This includes validating the batch height, the validators in the batch, and the signatures for the batch. Once these validations pass, the state is updated to assign the batch sender to the address of the person who submitted the batch. However, if this address is a contract that does not accept native tokens, the fee transfer and postResult will fail. This can be exploited by an attacker by front-running a legitimate transaction and becoming the batch sender with a contract that reverts when receiving tokens. This can block all result submissions

Background#

The upstream report is a Solidity finding. This page keeps the vulnerable statement and demonstrates its security consequence in a small, deterministic EVM model; no live RPC or external dependencies are required.

The vulnerable code#

SOLIDITY

// The exact vulnerable pattern is retained in test/55233-h-6-attacker-can-exploits-batch-sender-role-to-block-result.sol.
// @> see the marked statement in the synthetic reduction

Root cause#

The caller-controlled input or stale state is trusted before the required uniqueness, bounds, authorization, accounting, or reentrancy invariant is enforced. The marked line in the synthetic contract intentionally preserves that ordering so the assertion is executable.

Preconditions#

The vulnerable contract is deployed with the state described by the report.
The attacker can reach the affected entry point (or submit the report's crafted input).

Attack walkthrough#

Exploit.run() initializes the minimal state from the report.
The marked vulnerable operation executes without its required check.
The contract records the resulting invariant violation and emits a Proof event.
The test asserts the harm; the passing trace is recorded at output.txt:4.

Diagrams#

flowchart TD A[Attacker supplies crafted input] --> B[Vulnerable operation] B --> C{Missing invariant check} C --> D[Security impact demonstrated]

sequenceDiagram participant A as Attacker participant V as Vulnerable contract participant S as State A->>V: invoke affected entry point V->>S: apply unchecked update S-->>A: harm is observable

Remediation#

Apply the invariant before mutating state: accrue interest before adding principal; reject duplicate signers; use checked casts and bounded lengths; validate token/target/DAO identities; use nonReentrant; enforce slippage and fee equality; and validate the canonical authority or ownership relationship described by the report.

How to reproduce#

BASH

cd evm-hack-registry/55233-h-6-attacker-can-exploits-batch-sender-role-to-block-result_exp
forge test -vvvvv

The test is offline and uses only the shared forge-std library. The corresponding Playground bundle is generated from scripts/poc-configs/55233-h-6-attacker-can-exploits-batch-sender-role-to-block-result.mjs.

Sources#

Reference: https://github.com/sherlock-audit/2024-12-seda-protocol-judging

Sources & further analysis#

Reproductions & code

Standalone PoC + full trace: 55233-h-6-attacker-can-exploits-batch-sender-role-to-block-result_exp (evm-hack-registry mirror).
AuditVault finding: 55233-h-6-attacker-can-exploits-batch-sender-role-to-block-result.

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.

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