bridge-exploit

bridge-exploit is a skill for Claude Code from MingyiSecLab/Mingyi-Atlas. It costs 62 tokens per session (1,348 once invoked), scanned A, a copy of contracts-bridge-exploit, Apache-2.0.

A security-audit guide for finding attacks against cross-chain bridges, which move assets or messages between blockchains. It covers forged messages, stolen validator keys, reentrancy, fake Merkle proofs, and signature replay.

In plain words
What is it for?
Use it to review bridge message validation, validator security, token claims, Merkle proofs, and cross-chain signatures.
Why use it?
Cross-chain bridges depend on complicated trust and verification systems, so mistakes can let attackers mint or withdraw assets without authorization.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it to review bridge message validation, validator security, token claims, Merkle proofs, and cross-chain signatures.

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Install with agentmods
npx agentmods add skills/mingyiseclab/mingyi-atlas/bridge-exploit
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add MingyiSecLab/Mingyi-Atlas --skill bridge-exploit
Clone the repo
git clone --depth 1 https://github.com/MingyiSecLab/Mingyi-Atlas

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for bridge-exploit

README.md
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Your own site
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Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for bridge-exploit

Your own site · 80×15
<a href="https://agentmods.dev/skills/mingyiseclab/mingyi-atlas/bridge-exploit"><img src="https://agentmods.dev/badge/skills/mingyiseclab/mingyi-atlas/bridge-exploit.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,348 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 98% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00062 $0.01348
Opus 5 $0.00031 $0.00674
Sonnet 5 $0.00012 $0.00270
Haiku 4.5 $0.00006 $0.00135

Measured 9d ago against content hash 19a0be071f92, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

bridge-exploit scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

98% identical to contracts-bridge-exploit — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

src/skills/standard/contracts/bridge-exploit/SKILL.md · 115 lines

How it starts

The opening of the file, as written. The whole thing — 115 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cross-Chain Bridge Attack

Bridges hold large pooled assets and execute messages from a separate trust layer. Architecturally fragile.

Bridge taxonomy

Type Trust model Past exploits
Lock-and-mint Trusted validators sign mint events Wormhole ($325M), Ronin ($600M), Harmony ($100M)
Burn-and-redeem Same Multichain/Anyswap ($126M)
Optimistic Fraud proof window Nomad ($190M)
Light-client / zk Cryptographic (Fewer hacks, but newer)
Liquidity-network (Hop, Connext) Routers + relayers Smaller individual exploits

Attack classes

1. Validator-signature bypass (Wormhole, Feb 2022, $325M)

The Solana-side verify_signature function trusted the caller to provide a "verified" sigset account. Attacker passed a sysvar that wasn't a real sigset → unauthorized mint of 120k wETH.

Lesson: any verify function whose input is a struct fetched by address is bypassable if address-trust is missing.

2. Validator key compromise (Ronin, March 2022, $600M)

9-of-9 validators, 5 of which were operated by one entity. Sky Mavis got phished → attacker controlled 5 keys → arbitrary mint.

Lesson: validator decentralization isn't math, it's operational. Count distinct legal entities and key-storage methods, not just keys.

3. Merkle-proof forgery (Nomad, August 2022, $190M)

After an upgrade, the zero-hash was set as a "valid root" — any proof against root = 0 passed. The first attacker withdrew real funds; then thousands of others copy-pasted the same tx with their own address. ~$190M total.

Lesson: check initialize / upgrade scripts for accidental defaults — bytes32(0), address(0), 1 (often the most-tested value) becoming the trusted value.

4. Replay across chains (Multichain class)

Bridge tx signed for chain A is replayed on chain B because chainId wasn't bound into the signed message:

function claim(bytes32 nonce, uint256 amount, bytes calldata sig) external {
    bytes32 hash = keccak256(abi.encode(nonce, msg.sender, amount));   // ⚠ no chainId
    require(ecrecover(hash, ...) == validator);
    token.transfer(msg.sender, amount);
}
// On chain A: legit claim
// On chain B (same validator, same token): replay the same sig

Read the full file on GitHub · 115 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 115 lines · 62 tokens per session scan A 19a0be071f92

Subscribe to this mod's changes

bridge-exploit is a skill published in the GitHub repository MingyiSecLab/Mingyi-Atlas (11 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 62 tokens to every session and 1,348 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 98% identical to contracts-bridge-exploit, differing in 2 lines, and is treated as a copy.