Aave DIVA Wrapper

Issue Overview

The AaveDIVAWrapper contract does not validate duplicate tokens in batch registrations. This allows users to submit the same collateral token multiple times, leading to:

• Denial of service (DoS) if duplicate entries cause reverts.

• Inconsistencies in collateral mappings, potentially leading to unexpected protocol behavior.

• Operational disruptions, as failed batch transactions waste gas and affect users.

Root Cause

Lack of Duplicate Detection in Batch Processing

Batch functions directly iterate over user-provided input arrays without checking for duplicate tokens before calling _registerCollateralToken.

Vulnerable Code Snippet

Problem:

• If a duplicate token is processed, it may revert or cause unintended mapping updates.

• If _registerCollateralToken does not handle duplicates, it could overwrite existing mappings, leading to data corruption.

Attack Vector

Duplicate Collateral Registration Leading to DoS

Scenario: User Submits a Duplicate Token in Batch

1. Step 1: A user submits a batch request with the same collateral token twice.

2. Step 2: The _registerCollateralToken function processes the first instance successfully.

3. Step 3: The second instance is processed, potentially causing:

   • A revert if _registerCollateralToken rejects duplicates.

   • An overwrite of collateral mappings if duplicates are not properly handled.

4. Step 4: If the transaction reverts, no tokens in the batch are processed, causing a DoS for legitimate users.

Common Scenario Will Happen

Protocol Disruption via Duplicate Token Registration

Scenario: Exchange Adds Multiple Collateral Tokens

1. A DEX integrates AaveDIVAWrapper and attempts to register 100 collateral tokens at once.

2. Due to a frontend bug, two tokens are accidentally duplicated in the batch request.

3. The entire batch transaction fails, forcing the DEX to retry manually.

4. Consequence:

   • The exchange wastes gas fees on failed transactions.

   • Users cannot add new collateral tokens until the issue is resolved.

   • The protocol loses credibility due to unexpected reverts.

Impact

Severity: Medium

✅ Likelihood: High – No restrictions prevent duplicate registrations.
✅ Impact: Moderate – Causes DoS and inconsistencies in the protocol's mapping system.

Potential Consequences

1. Denial of Service (DoS):

   • Users cannot register legitimate tokens if batch transactions fail.

   • Exchanges face transaction failures, reducing usability.

2. Protocol Mapping Inconsistencies:

   • Duplicate registrations could cause unexpected collateral behavior.

   • If a mapping is overwritten, previous data may be lost.

3. User Frustration & Gas Wastage:

   • Users pay gas fees for transactions that fail due to duplicates.

   • Lack of proper error handling could make troubleshooting difficult.

Proof of Concept (PoC)

Solidity contract demonstrates how duplicate registrations cause batch failures.

Exploit Code: Duplicate Token Registration

Expected Outcome

✅ The batch transaction fails completely due to duplicate entries.
✅ Gas fees are wasted and no collateral tokens are registered.

Solution

1. Implement Duplicate Detection Before Processing

✅ Fix: Pre-Validation in Batch Functions

Before executing _registerCollateralToken, ensure no duplicates exist in the input array.

✅ Ensures no duplicate tokens are processed.
✅ Prevents transaction failures due to duplicate entries.
✅ Enhances batch transaction reliability.

2. Validate Against Existing Mappings

✅ Fix: Prevent Overwriting Existing Tokens

✅ Prevents re-registering existing collateral tokens.
✅ **Ensures protocol data integrity remains intact. **