The Future of Auditing Is Context-Aware: Understanding UserOp Flows

Traditional audits check smart contracts in isolation, but the real risk is in the handoff. A safe dApp + a safe wallet + a safe bridge can still create a vulnerable flow. The exploit lives in the transaction path, not the endpoints.

• Blind Spot: Cross-chain intent execution between UniswapX and Across.
• Real Risk: $2B+ in cross-chain volume flows through these opaque paths daily.

Map every UserOp as a state machine. Track the wallet → dApp → solver → executor lifecycle in real-time. This creates an auditable graph of dependencies and privileges.

• Key Insight: Model ERC-4337 Bundler and Paymaster interactions as a directed graph.
• Actionable Intel: Flag anomalies like a Paymaster draining gas from a seemingly unrelated AAVE position.

Define and enforce security policies across the entire flow. "This wallet can only interact with these Curve pools via this specific Safe{Wallet} module." It's a firewall for user intent.

• Prevents: Sandwich attacks by restricting MEV bot routing via CowSwap.
• Enables: Role-based flow permissions for institutional smart accounts.

This is our product. It's a real-time monitoring layer that instruments the EVM call stack across a UserOp's lifecycle. We tag flows, score risk, and automate response.

• Core Tech: EVM bytecode instrumentation + intent graph analysis.
• Integration: Plugs into Tenderly for simulation and Forta for alerting.

Auditors see a contract's code, not the user's journey. A safe function can be weaponized when called via a malicious frontend or nested bundle.\n- ~$1B+ in losses from approval phishing and flow manipulation.\n- 0 visibility into cross-contract, cross-domain intent.

Map the actual execution path of a UserOp from signer to settlement. This creates a context-aware audit trail.\n- Tracks cross-contract calls, delegatecalls, and bridge interactions.\n- Flags anomalous patterns like sudden fee spikes or unexpected token approvals.

Already building the primitive with simulation and debugging. The next step is automated flow policy enforcement.\n- Simulates full transaction traces before execution.\n- Potential to layer risk scoring on top of live UserOp streams for wallets like Safe.

Intents via UniswapX or CowSwap delegate execution complexity. Auditing the solver is not auditing the user's guaranteed outcome.\n- Solver risk becomes user risk.\n- Impossible to verify fulfillment matches signer's expectation without a flow standard.

Audit stacks must verify claims about remote state. Did the funds actually arrive on the destination chain?\n- Integrates with light clients like Succinct or Herodotus.\n- Closes the loop for bridges like Across and messaging layers like LayerZero.

Even a perfectly secure flow can be economically hostile. The audit stack must model extractable value.\n- Analyzes gas auctions, sandwichability, and PBS dynamics.\n- Quantifies the real cost of a UserOp beyond gas fees.

ERC-4337 Bundlers execute UserOps without understanding the full intent chain. A harmless swap approval can be front-run by a malicious dApp to drain assets.\n- Vulnerability: Isolated tx checks miss cross-contract dependencies.\n- Attack Vector: Session keys or validateUserOp logic exploited post-verification.

Auditors must simulate the full UserOp flow, not just the entry point. This requires tracking state changes across all involved contracts like Uniswap, Aave, and layerZero.\n- Key Benefit: Catches logic errors in batched operations (e.g., swap-then-bridge).\n- Key Benefit: Validates gas sponsorship and fee logic end-to-end.

Paymasters like Biconomy or Stackup abstract gas, but create a single point of censorship and failure. A compromised or malicious paymaster can block, front-run, or tamper with UserOps.\n- Vulnerability: Trusted third party controls transaction lifecycle.\n- Attack Vector: Paymaster rug-pull or regulatory compliance shutdown.

Security requires a network of independent verifiers (e.g., a zk-Proof of Solvency model) to validate paymaster behavior and UserOp integrity. Think of it as a decentralized watchtower for 4337.\n- Key Benefit: Eliminates single-entity trust for gas sponsorship.\n- Key Benefit: Enables real-time fraud proof submission to the EntryPoint.

Intent solvers like UniswapX, CowSwap, and Across use complex, off-chain algorithms. Users delegate routing decisions, creating a black box risk where the optimal route may be manipulated for validator/MEV profit.\n- Vulnerability: No on-chain guarantee of execution quality.\n- Attack Vector: Solver extracts value via sandwich attacks or poor exchange rates.

Auditing must shift to verifying the cryptographic proofs of execution correctness provided by intent solvers. This requires new standards for disclosing routing logic and proving best execution.\n- Key Benefit: On-chain verification of solver performance claims.\n- Key Benefit: Enables enforceable SLAs and automatic slashing for violations.