Mamo PR Audit | Moonwell | Halborn Audit Reports

Summary

100% of all REPORTED Findings have been addressed

About this report

Assessment Type

Assurance Assessment

Date of Engagement

June 18th, 2025 - June 18th, 2025

Source Code

mamo-contracts

Assessed Commit ID

c75d06a

Severity Breakdown

0Risk Accepted
7Acknowledged
2Solved
9All Findings

Critical0
High0
Medium1
- 1Solved
Low1
- 1Solved
Informational7
- 7Ack.

Summary#

Introduction#

Moonwell engaged Halborn to conduct a security assessment on their smart contracts beginning on June 18th, 2025 and ending on June 19th, 2025. The security assessment was scoped to the smart contracts provided to Halborn. Commit hash and further details can be found in the Scope section of this report.

The smart contracts under review consisted of StrategyFactory, a Factory contract for creating new strategy instances with configurable parameters, and StrategyMulticall, a contract to allow efficient batch updates and generic multicalls to strategies. Furthermore, the security review also added the upgrade of the SlippagePriceChecker contract to make sure no risks were introduced nor storage collisions.

Assessment Summary#

Halborn was provided 2 days for the engagement, and assigned one full-time security engineer to review the security of the smart contracts in scope. The engineer is a blockchain and smart contract security expert with advanced penetration testing and smart contract hacking skills, and deep knowledge of multiple blockchain protocols.

The objectives of this assessment were to

Identify potential security issues within the smart contracts.
Ensure that smart contract functionality operates as intended.

In summary, Halborn identified some improvements to reduce the likelihood and impact of risks, which were completely addressed by the Moonwell team. The main ones were the following:

Consider refunding excess funds in genericMulticall() or add a withdraw functionallity.
Add a reentrancy protection to the genericMulticall() function in StrategyMulticall.

Test Approach and Methodology#

Halborn performed a combination of manual and automated security testing to balance efficiency, timeliness, practicality, and accuracy in regard to the scope of this assessment. While manual testing is recommended to uncover flaws in logic, process, and implementation; automated testing techniques help enhance coverage of the code and can quickly identify items that do not follow the security best practices. The following phases and associated tools were used during the assessment:

Research into architecture and purpose.
Smart contract manual code review and walkthrough.
Graphing out functionality and contract logic/connectivity/functions (solgraph).
Manual assessment of use and safety for the critical Solidity variables and functions in scope to identify any arithmetic related vulnerability classes.
Manual testing by custom scripts.
Static Analysis of security for scoped contract, and imported functions (slither).
Testnet deployment (Foundry).

Storage collision Assessment#

Storage collision study was performed as part of this security review. The original SlippagePriceChecker only used Slot 0 and Slot 1:

BASH

forge inspect src/SlippagePriceChecker.sol:SlippagePriceChecker storage 

╭-------------------+---------------------------------------------------------------------------+------+--------+-------+---------------------------------------------------╮
| Name              | Type                                                                      | Slot | Offset | Bytes | Contract                                          |
+===========================================================================================================================================================================+
| tokenOracleData   | mapping(address => struct ISlippagePriceChecker.TokenFeedConfiguration[]) | 0    | 0      | 32    | src/SlippagePriceChecker.sol:SlippagePriceChecker |
|-------------------+---------------------------------------------------------------------------+------+--------+-------+---------------------------------------------------|
| maxTimePriceValid | mapping(address => uint256)                                               | 1    | 0      | 32    | src/SlippagePriceChecker.sol:SlippagePriceChecker |
╰-------------------+---------------------------------------------------------------------------+------+--------+-------+---------------------------------------------------╯

The new SlippagePriceChecker uses Slot 0, Slot 1 and Slot 2:

BASH

forge inspect src/SlippagePriceChecker.sol:SlippagePriceChecker storage

╭---------------------+-----------------------------------------------------------------------------------------------+------+--------+-------+---------------------------------------------------╮
| Name                | Type                                                                                          | Slot | Offset | Bytes | Contract                                          |
+=================================================================================================================================================================================================+
| tokenOracleData     | mapping(address => struct ISlippagePriceChecker.TokenFeedConfiguration[])                     | 0    | 0      | 32    | src/SlippagePriceChecker.sol:SlippagePriceChecker |
|---------------------+-----------------------------------------------------------------------------------------------+------+--------+-------+---------------------------------------------------|
| maxTimePriceValid   | mapping(address => uint256)                                                                   | 1    | 0      | 32    | src/SlippagePriceChecker.sol:SlippagePriceChecker |
|---------------------+-----------------------------------------------------------------------------------------------+------+--------+-------+---------------------------------------------------|
| tokenPairOracleData | mapping(address => mapping(address => struct ISlippagePriceChecker.TokenFeedConfiguration[])) | 2    | 0      | 32    | src/SlippagePriceChecker.sol:SlippagePriceChecker |
╰---------------------+-----------------------------------------------------------------------------------------------+------+--------+-------+---------------------------------------------------╯

Therefore, no potential collisions were observed.

Risk Methodology#

Every vulnerability and issue observed by Halborn is ranked based on two sets of Metrics and a Severity Coefficient. This system is inspired by the industry standard Common Vulnerability Scoring System.

The two Metric sets are: Exploitability and Impact. Exploitability captures the ease and technical means by which vulnerabilities can be exploited and Impact describes the consequences of a successful exploit.

The Severity Coefficients is designed to further refine the accuracy of the ranking with two factors: Reversibility and Scope. These capture the impact of the vulnerability on the environment as well as the number of users and smart contracts affected.

The final score is a value between 0-10 rounded up to 1 decimal place and 10 corresponding to the highest security risk. This provides an objective and accurate rating of the severity of security vulnerabilities in smart contracts.

The system is designed to assist in identifying and prioritizing vulnerabilities based on their level of risk to address the most critical issues in a timely manner.

6.1 EXPLOITABILITY

Attack Origin (AO):

Captures whether the attack requires compromising a specific account.

Attack Cost (AC):

Captures the cost of exploiting the vulnerability incurred by the attacker relative to sending a single transaction on the relevant blockchain. Includes but is not limited to financial and computational cost.

Attack Complexity (AX):

Describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability. Includes but is not limited to macro situation, available third-party liquidity and regulatory challenges.

Metrics:

EXPLOITABILITY METRIC ( $m_e$ )	METRIC VALUE	NUMERICAL VALUE
Attack Origin (AO)	Arbitrary (AO:A)	1
Attack Origin (AO)	Specific (AO:S)	0.2
Attack Cost (AC)	Low (AC:L)	1
	Medium (AC:M)	0.67
	High (AC:H)	0.33
Attack Complexity (AX)	Low (AX:L)	1
	Medium (AX:M)	0.67
	High (AX:H)	0.33

Exploitability

E

is calculated using the following formula:

$E = \prod m_e$

6.2 IMPACT

Confidentiality (C):

Measures the impact to the confidentiality of the information resources managed by the contract due to a successfully exploited vulnerability. Confidentiality refers to limiting access to authorized users only.

Integrity (I):

Measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of data stored and/or processed on-chain. Integrity impact directly affecting Deposit or Yield records is excluded.

Availability (A):

Measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. This metric refers to smart contract features and functionality, not state. Availability impact directly affecting Deposit or Yield is excluded.

Deposit (D):

Measures the impact to the deposits made to the contract by either users or owners.

Yield (Y):

Measures the impact to the yield generated by the contract for either users or owners.

Metrics:

IMPACT METRIC ( $m_I$ )	METRIC VALUE	NUMERICAL VALUE
Confidentiality (C)	None (C:N)	0
	Low (C:L)	0.25
	Medium (C:M)	0.5
	High (C:H)	0.75
	Critical (C:C)	1
Integrity (I)	None (I:N)	0
	Low (I:L)	0.25
	Medium (I:M)	0.5
	High (I:H)	0.75
	Critical (I:C)	1
Availability (A)	None (A:N)	0
	Low (A:L)	0.25
	Medium (A:M)	0.5
	High (A:H)	0.75
	Critical (A:C)	1
Deposit (D)	None (D:N)	0
	Low (D:L)	0.25
	Medium (D:M)	0.5
	High (D:H)	0.75
	Critical (D:C)	1
Yield (Y)	None (Y:N)	0
	Low (Y:L)	0.25
	Medium (Y:M)	0.5
	High (Y:H)	0.75
	Critical (Y:C)	1

Impact

I

is calculated using the following formula:

$I = max(m_I) + \frac{\sum{m_I} - max(m_I)}{4}$

6.3 SEVERITY COEFFICIENT

Reversibility (R):

Describes the share of the exploited vulnerability effects that can be reversed. For upgradeable contracts, assume the contract private key is available.

Scope (S):

Captures whether a vulnerability in one vulnerable contract impacts resources in other contracts.

Metrics:

SEVERITY COEFFICIENT ( $C$ )	COEFFICIENT VALUE	NUMERICAL VALUE
Reversibility ( $r$ )	None (R:N)	1
	Partial (R:P)	0.5
	Full (R:F)	0.25
Scope ( $s$ )	Changed (S:C)	1.25
Scope ( $s$ )	Unchanged (S:U)	1

Severity Coefficient

C

is obtained by the following product:

$C = rs$

The Vulnerability Severity Score

S

is obtained by:

$S = min(10, EIC * 10)$

The score is rounded up to 1 decimal places.

Critical	High	Medium	Low	Informational
9 - 10	7 - 8.9	4.5 - 6.9	2 - 4.4	0 - 1.9

Scope#

(a) Repository:mamo-contracts

(b) Assessed Commit ID:c75d06acf50dabca17dc1d5d79ca9d1444d64480

3 files

src

3 files

SlippagePriceChecker.sol

solidity

StrategyFactory.sol

solidity

StrategyMulticall.sol

solidity

Out-of-Scope:Third party dependencies and economic attacks.

37bc9da4f038bb1602817d734681e4d043d2b2e9 24bb0862a8ef1eeb7ca64d7530f6fde611bdec9a

Out-of-Scope: New features/implementations after the remediation commit IDs.

Assessment Summary & Findings Overview#

#	Title	Severity	Score	Status
HAL-01	Excess Value Becomes Irrecoverable	Medium	5.0	Solved06/20/2025
HAL-02	Missing Reentrancy Protection in StrategyMulticall	Low	2.5	Solved06/23/2025
HAL-03	Single-step Ownership Transfer Process	Informational	1.7	Acknowledged06/25/2025
HAL-04	Owner Can Renounce Ownership	Informational	1.7	Acknowledged06/25/2025
HAL-05	Inaccurate NatSpec Comments	Informational	1.1	Acknowledged06/25/2025
HAL-06	Unused Imports	Informational	0.0	Acknowledged06/25/2025
HAL-07	Use of Revert Strings Instead of Custom Errors	Informational	0.0	Acknowledged06/25/2025
HAL-08	Redundant Named Return	Informational	0.0	Acknowledged06/25/2025
HAL-09	Style Guide Optimizations	Informational	0.0	Acknowledged06/25/2025

Findings & Tech Details#

HAL-01Solved

Excess Value Becomes Irrecoverable

Medium

5.0AO:A/AC:L/AX:L/R:N/S:U/C:N/A:N/I:N/D:M/Y:NAO:A/AC:L/AX:L/R:N/S:U/C:N/A:N/I:N/D:M/Y:N

Description

Recommendation

Remediation Comment

Addressed in:

37bc9da4f038bb1602817d734681e4d043d2b2e9

HAL-02Solved

Missing Reentrancy Protection in StrategyMulticall

Low

2.5AO:A/AC:L/AX:L/R:N/S:U/C:N/A:N/I:N/D:L/Y:NAO:A/AC:L/AX:L/R:N/S:U/C:N/A:N/I:N/D:L/Y:N

Description

Recommendation

Remediation Comment

Addressed in:

Remediation Comment

10. Automated Testing#

Disclaimer#

Halborn strongly recommends conducting a follow-up assessment of the project either within six months or immediately following any material changes to the codebase, whichever comes first. This approach is crucial for maintaining the project’s integrity and addressing potential vulnerabilities introduced by code modifications.