Stability Vault Audit | OpenEden | Halborn Audit Reports

Summary

100% of all REPORTED Findings have been addressed

About this report

Assessment Type

Assurance Assessment

Date of Engagement

July 4th, 2025 - July 4th, 2025

Source Code

usdo.tge.audit

Assessed Commit ID

127f22b

Severity Breakdown

0Risk Accepted
1Acknowledged
1Solved
2All Findings

Critical0
High0
Medium0
Low1
- 1Solved
Informational1
- 1Ack.

Introduction#

OpenEden engaged Halborn to conduct a security assessment of their smart contracts, beginning and concluding on July 4th, 2025. The scope of the assessment was limited to the smart contracts provided in the OpenEdenHQ/usdo.tge.audit GitHub repository supplied to Halborn. Additional details can be found in the Scope section of this report.

Assessment Summary#

Halborn was allocated one day for this engagement and assigned one full-time security engineer to review the in-scope smart contracts. The engineer is a blockchain and smart contract security specialist with advanced skills in penetration testing and smart contract auditing, possessing deep expertise across multiple blockchain protocols.

The objectives of the assessment are to:

Identify potential security vulnerabilities within the smart contracts.
Verify that smart contract functionality operates as intended.

In summary, Halborn identified several improvements to mitigate the likelihood and impact of potential risks, which were partially addressed by the OpenEden team. The key recommendations are as follows:

Modify the deposit condition to >= unlockTime to prevent deposits at the exact unlock timestamp, thereby ensuring clearer lock semantics.
Use the exact duration in seconds or explicitly document the 30-day month approximation to set accurate user expectations regarding unlock timing.

Caveats#

The commit 5961045, which introduces the new feature, phased distribution of forfeited tokens between stability mechanisms and treasury management, is outside the scope of this assessment.

Test Approach and Methodology#

Halborn employed a combination of manual, semi-automated, and automated security testing methodologies to ensure thoroughness, efficiency, and accuracy within the scope of this assessment. Manual testing is essential for uncovering vulnerabilities related to logic, process, and implementation, while automated tools enhance code coverage and quickly identify deviations from security best practices. The assessment comprised the following phases and tools:

Research into the architecture and purpose of the smart contracts.
Manual review and walkthrough of the smart contract code.
Manual evaluation of critical Solidity variables and functions to identify potential vulnerability classes.
Manual testing utilizing custom scripts.
Static security analysis of the scoped contracts and imported functions using Slither.
Local deployment and testing with Foundry.

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.

5.1 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:

$E = \prod m_e$

5.2 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:

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

5.3 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:usdo.tge.audit

(b) Assessed Commit ID:127f22be9201a0244f3533deeaf81bafbfb5fd31

1 files

contracts

1 file

StabilityVault.sol

solidity

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

1dd6e417e40ac9eb9d8d1974272df05f97757dac

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

Assessment Summary & Findings Overview#

#	Title	Severity	Score	Status
HAL-01	Deposit allowed at exact unlock timestamp	Low	2.5	Solved07/11/2025
HAL-02	Lock-period “month” approximation	Informational	0.0	Acknowledged07/16/2025

Findings & Tech Details#

HAL-01Solved

Deposit allowed at exact unlock timestamp

Low

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

Description

Recommendation

Remediation Comment

Addressed in:

1dd6e417e40ac9eb9d8d1974272df05f97757dac

HAL-02Acknowledged

Lock-period “month” approximation

Informational

0.0AO:A/AC:L/AX:L/R:N/S:U/C:N/A:N/I:N/D:N/Y:NAO:A/AC:L/AX:L/R:N/S:U/C:N/A:N/I:N/D:N/Y:N

Description

Recommendation

Remediation Comment

9. 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.