Earn V1 - Blueprint Finance

Prepared by:

HALBORN

Last Updated Unknown date

Date of Engagement: April 22nd, 2024 - July 19th, 2024

Summary

100% of all REPORTED Findings have been addressed

All findings

Critical

High

Medium

Low

Informational

1. Introduction
2. Assessment summary
3. Test approach and methodology

3.1 Out-of-scope

4. Risk methodology
5. Scope
6. Assessment summary & findings overview
7. Findings & Tech Details

7.1 Logic issue on vault removal
7.2 Potential denial of service on prepare withdrawal function
7.3 Denial of service on _getstrategy function
7.4 Claimrouter contract is using a mock interface
7.5 Unchecked return values of erc20 functions
7.6 Single step ownership transfer process
7.7 Owner can renounce ownership
7.8 A single compromised account can lock up the protocol
7.9 Potential denial of service on removevault with block gas limit
7.10 Checked increments in for loops increases gas consumption
7.11 Incomplete error handling in retirestrategy
7.12 Missing checks for index out of bounds
7.13 Use external instead of public methods
7.14 Push0 is not supported by all chains
7.15 Missing zero address checks
7.16 Checked increments in for loops increases gas consumption
7.17 Lack of validation on protectstrategy
7.18 Duplicated imports
7.19 Events for function calls
7.20 Centralization risk: lack of access control in requestfunds
7.21 Missing zero address checks on constructor
7.22 Unrestricted reward enabling
7.23 Centralization risk: retirestrategy
7.24 No events for claim function

1. Introduction

Concrete engaged Halborn to conduct a security assessment on their smart contracts. This report includes four assessments carried out on the following schedules:

Money Printer assessment beginning on April 22nd, 2024 and ending on May 1st, 2024.
Money Printer Code Updates assessment beginning on May 20th, 2024 and ending on June 5th, 2024.
Earn diff assessment beginning on June 10th, 2024 and ending on June 17th, 2024.
Silo and Radiant Strategies assessment beginning on July 16th, 2024 and ending on July 19th, 2024.

2. Assessment Summary

The team at Halborn was provided one week for the engagement and assigned a full-time security engineer to verify the security of the smart contract. The security engineer is a blockchain and smart-contract security expert with advanced penetration testing, smart-contract hacking, and deep knowledge of multiple blockchain protocols.

The purpose of this assessment is to:

Ensure that smart contract functions operate as intended.
Identify potential security issues with the smart contracts.

In summary, Halborn identified some security risks that were mostly addressed/acknowledged by the Concrete team.

3. 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.
Testnet deployment (Foundry).

3.1 Out-of-scope

External libraries and financial-related attacks.
Files located under src/examples/* folder.

4. 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.

4.1 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) Specific (AO:S)	1 0.2
Attack Cost (AC)	Low (AC:L) Medium (AC:M) High (AC:H)	1 0.67 0.33
Attack Complexity (AX)	Low (AX:L) Medium (AX:M) High (AX:H)	1 0.67 0.33

Exploitability

E

is calculated using the following formula:

$E = \prod m_e$

4.2 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) Low (C:L) Medium (C:M) High (C:H) Critical (C:C)	0 0.25 0.5 0.75 1
Integrity (I)	None (I:N) Low (I:L) Medium (I:M) High (I:H) Critical (I:C)	0 0.25 0.5 0.75 1
Availability (A)	None (A:N) Low (A:L) Medium (A:M) High (A:H) Critical (A:C)	0 0.25 0.5 0.75 1
Deposit (D)	None (D:N) Low (D:L) Medium (D:M) High (D:H) Critical (D:C)	0 0.25 0.5 0.75 1
Yield (Y)	None (Y:N) Low (Y:L) Medium (Y:M) High (Y:H) Critical (Y:C)	0 0.25 0.5 0.75 1

Impact

I

is calculated using the following formula:

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

4.3 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) Partial (R:P) Full (R:F)	1 0.5 0.25
Scope ( $s$ )	Changed (S:C) Unchanged (S:U)	1.25 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.

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

5. SCOPE

REPOSITORY

(a) Repository: sc_earn-v1

(b) Assessed Commit ID: 949c177

src/vault/ConcreteMultiStrategyVault.sol
src/swapper/Swapper.sol
src/swapper/OraclePlug.sol

↓ Expand ↓

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

6. Assessment Summary & Findings Overview

Critical

High

Medium

Low

Informational

Security analysis	Risk level	Remediation Date
Logic issue on vault removal	Medium	Solved - 07/29/2024
Potential Denial of Service on prepare withdrawal function	Low	Risk Accepted
Denial of service on _getStrategy function	Low	Solved - 06/09/2024
ClaimRouter contract is using a mock interface	Low	Risk Accepted
Unchecked Return Values of ERC20 Functions	Low	Solved - 07/29/2024
Single step ownership transfer process	Informational	Acknowledged
Owner can renounce Ownership	Informational	Acknowledged
A single compromised account can lock up the protocol	Informational	Acknowledged
Potential denial of service on removeVault with block gas limit	Informational	Solved - 06/09/2024
Checked increments in for loops increases gas consumption	Informational	Solved - 05/07/2024
Incomplete Error Handling in retireStrategy	Informational	Solved - 07/29/2024
Missing checks for index out of bounds	Informational	Solved - 05/07/2024
Use external instead of public methods	Informational	Solved - 05/07/2024
PUSH0 is not supported by all chains	Informational	Acknowledged
Missing zero address checks	Informational	Acknowledged
Checked increments in for loops increases gas consumption	Informational	Acknowledged
Lack of validation on ProtectStrategy	Informational	Acknowledged
Duplicated Imports	Informational	Solved - 07/30/2024
Events for Function Calls	Informational	Acknowledged
Centralization risk: Lack of Access Control in requestFunds	Informational	Acknowledged
Missing zero address checks on constructor	Informational	Solved - 07/29/2024
Unrestricted Reward Enabling	Informational	Acknowledged
Centralization risk: retireStrategy	Informational	Acknowledged
No Events for claim function	Informational	Acknowledged

7. Findings & Tech Details

7.1 Logic issue on vault removal

Medium

Description

BVSS

AO:A/AC:L/AX:L/C:N/I:N/A:N/D:N/Y:N/R:N/S:C (0.0)

Recommendation

Remediation Comment

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.

1. Introduction
2. Assessment summary
3. Test approach and methodology

3.1 Out-of-scope

4. Risk methodology
5. Scope
6. Assessment summary & findings overview
7. Findings & Tech Details

7.1 Logic issue on vault removal
7.2 Potential denial of service on prepare withdrawal function
7.3 Denial of service on _getstrategy function
7.4 Claimrouter contract is using a mock interface
7.5 Unchecked return values of erc20 functions
7.6 Single step ownership transfer process
7.7 Owner can renounce ownership
7.8 A single compromised account can lock up the protocol
7.9 Potential denial of service on removevault with block gas limit
7.10 Checked increments in for loops increases gas consumption
7.11 Incomplete error handling in retirestrategy
7.12 Missing checks for index out of bounds
7.13 Use external instead of public methods
7.14 Push0 is not supported by all chains
7.15 Missing zero address checks
7.16 Checked increments in for loops increases gas consumption
7.17 Lack of validation on protectstrategy
7.18 Duplicated imports
7.19 Events for function calls
7.20 Centralization risk: lack of access control in requestfunds
7.21 Missing zero address checks on constructor
7.22 Unrestricted reward enabling
7.23 Centralization risk: retirestrategy
7.24 No events for claim function

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Earn V1

Blueprint Finance

Table of Contents

1. Introduction

2. Assessment Summary

3. Test Approach and Methodology

3.1 Out-of-scope

4. RISK METHODOLOGY

4.1 EXPLOITABILITY

Attack Origin (AO):

Attack Cost (AC):

Attack Complexity (AX):

Metrics:

4.2 IMPACT

Confidentiality (C):

Integrity (I):

Availability (A):

Deposit (D):

Yield (Y):

Metrics:

4.3 SEVERITY COEFFICIENT

Reversibility (R):

Scope (S):

Metrics:

5. SCOPE

6. Assessment Summary & Findings Overview

7. Findings & Tech Details

7.1 Logic issue on vault removal

Description

Proof of Concept

BVSS

Recommendation

Remediation Comment

7.2 Potential Denial of Service on prepare withdrawal function

Description

BVSS

Recommendation

Remediation Comment

7.3 Denial of service on _getStrategy function

Description

BVSS

Recommendation

Remediation Comment

7.4 ClaimRouter contract is using a mock interface

Description

BVSS

Recommendation

Remediation Comment

7.5 Unchecked Return Values of ERC20 Functions

Description

BVSS

Recommendation

Remediation Comment

7.6 Single step ownership transfer process

Description

BVSS

Recommendation

Remediation Comment

7.7 Owner can renounce Ownership

Description

BVSS

Recommendation

Remediation Comment

7.8 A single compromised account can lock up the protocol

Description

BVSS

Recommendation

Remediation Comment

7.9 Potential denial of service on removeVault with block gas limit

Description

BVSS

Recommendation

Remediation Comment

7.10 Checked increments in for loops increases gas consumption

Description

BVSS

Recommendation

Remediation Comment

7.11 Incomplete Error Handling in retireStrategy

Description