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Contracts Core and BSX Token (2nd round) - BSX Exchange

Prepared by:

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HALBORN

Last Updated Unknown date

Date of Engagement: October 9th, 2024 - October 23rd, 2024

Summary

100% of all REPORTED Findings have been addressed

All findings

11

Critical

0

High

1

Medium

4

Low

3

Informational

3

Table of Contents

1. Introduction

BSX engaged Halborn to conduct a security assessment on their smart contracts beginning on October 9th, 2024 and ending on October 23rd, 2024. The security assessment was scoped to the BSX Exchange smart contracts in the GitHub repository provided to the Halborn team. Commit hashes and further details can be found in the Scope section of this report.

2. Assessment Summary

Halborn was provided two weeks for the engagement and assigned one full-time security engineer to review the security of the smart contract 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 purpose of the assessment is 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 partially addressed by the BSX team. The main identified issues were the following:

    • Guarantee solvency when opening new positions

    • Disable intializers in contracts constructors

    • Initialize inherited contracts

    • Take all inputs into account when signing payloads to guarantee total integrity

    • Keep the storage variable in the same place between two versions of a contract

    • Prevent integer silent signed to unsigned casting

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 contracts' solidity code and can quickly identify items that do not follow security best practices. The following phases and associated tools were used throughout the term of the assessment:

    • Research into architecture and purpose.

    • Smart contract manual code review and walk-through.

    • Manual assessment of use and safety for the critical Solidity variables and functions in scope to identify any arithmetic-related vulnerability classes.

    • Local testing with custom scripts (Foundry).

    • Fork testing against main networks (Foundry).

    • Static analysis of security for scoped contract, and imported functions

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 (mem_e)METRIC VALUENUMERICAL 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 EE is calculated using the following formula:

E=∏meE = \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 (mIm_I)METRIC VALUENUMERICAL 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 II is calculated using the following formula:

I=max(mI)+∑mI−max(mI)4I = 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 (CC)COEFFICIENT VALUENUMERICAL VALUE
Reversibility (rr)None (R:N)
Partial (R:P)
Full (R:F)		1
0.5
0.25
Scope (ss)Changed (S:C)
Unchanged (S:U)		1.25
1
Severity Coefficient CC is obtained by the following product:

C=rsC = rs

The Vulnerability Severity Score SS is obtained by:

S=min(10,EIC∗10)S = min(10, EIC * 10)

The score is rounded up to 1 decimal places.
SeverityScore Value Range
Critical9 - 10
High7 - 8.9
Medium4.5 - 6.9
Low2 - 4.4
Informational0 - 1.9

5. SCOPE

REPOSITORIES
(a) Repository: contracts-core
(b) Assessed Commit ID: d932bdf
(c) Items in scope:
  • /1000x/BSX1000x.sol
  • /1000x/interfaces/IBSX1000x.sol
  • /exchange/ClearingService.sol
↓ Expand ↓
Out-of-Scope: Third party dependencies and economic attacks.
(a) Repository: bsx-token
(b) Assessed Commit ID: https://github.com/bsx-exchange/bsx-token/tree/ae321534940931779b8e7f550565c22890251ff8
(c) Items in scope:
  • BsxToken.sol
Out-of-Scope: Third party dependencies and economic attacks.
Out-of-Scope: New features/implementations after the remediation commit IDs.

6. Assessment Summary & Findings Overview

Critical

0

High

1

Medium

4

Low

3

Informational

3

Security analysisRisk levelRemediation Date
BSX1000 solvency not guaranteedHighSolved - 10/27/2024
Missing constructor disabling initializationMediumSolved - 10/27/2024
Missing initialization of inherited upgradable contractsMediumSolved - 10/27/2024
Payloads to sign do not include all input parametersMediumRisk Accepted - 10/27/2024
Removing storage variables in upgradable contractsMediumRisk Accepted - 10/27/2024
Integer unsafe casting issuesLowSolved - 10/27/2024
Order fees are charged twiceLowRisk Accepted - 10/27/2024
Truncated balance not accrued to fund balance after withdrawalLowRisk Accepted - 10/27/2024
ETH deposit does not validate the amount sentInformationalSolved - 10/27/2024
High fees can block the closing position processInformationalAcknowledged - 10/27/2024
Confusing error messagesInformationalSolved - 10/27/2024

7. Findings & Tech Details

7.1 BSX1000 solvency not guaranteed

//

High

Description
Proof of Concept
BVSS
Recommendation
Remediation Comment

7.2 Missing constructor disabling initialization

//

Medium

Description
Proof of Concept
BVSS
Recommendation
Remediation Comment

7.3 Missing initialization of inherited upgradable contracts

//

Medium

Description
BVSS
Recommendation
Remediation Comment

7.4 Payloads to sign do not include all input parameters

//

Medium

Description
BVSS
Recommendation
Remediation Comment

7.5 Removing storage variables in upgradable contracts

//

Medium

Description
BVSS
Recommendation
Remediation Comment

7.6 Integer unsafe casting issues

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.7 Order fees are charged twice

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.8 Truncated balance not accrued to fund balance after withdrawal

//

Low

Description
BVSS
Recommendation
Remediation Comment

7.9 ETH deposit does not validate the amount sent

//

Informational

Description
BVSS
Recommendation
Remediation Comment

7.10 High fees can block the closing position process

//

Informational

Description
BVSS
Recommendation
Remediation Comment

7.11 Confusing error messages

//

Informational

Description
BVSS
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.

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Contracts Core and BSX Token (2nd round)

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