Ten Protocol Audit | Obscu/TEN | Halborn Audit Reports

Summary

100% of all REPORTED Findings have been addressed

About this report

Assessment Type

Assurance Assessment

Date of Engagement

May 5th, 2025 - May 8th, 2025

Source Code

go-ten

Assessed Commit ID

6cae341

Severity Breakdown

5Partially Solved
4Acknowledged
3Risk Accepted
10Solved
22All Findings

Critical0
High0
Medium0
Low7
- 2Solved
- 2P. Solved
- 3Risk A.
Informational15
- 4Ack.
- 3P. Solved
- 8Solved

Introduction#

Ten Protocol engaged Halborn to conduct a security assessment on their smart contracts beginning on May 5th, 2025 and ending on May 8th, 2025. The security assessment was scoped to the smart contracts provided to Halborn. Commit hashes and further details can be found in the Scope section of this report.

The Ten Protocol codebase in scope mainly consists of an infrastructure with an upgradeable token system, cross-chain messaging, and transaction processing mechanisms.

Assessment Summary#

Halborn was provided 4 days for the engagement and assigned 1 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 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 Ten Protocol team. The main ones are the following:

Add validation in the canReattemptCallback modifier to ensure the callbackId exists.
Consider adding functionality to allow callback originators to cancel their pending callbacks when they're no longer needed or desired.
Consider implementing a comprehensive callback management system.

Test Approach and Methodology#

Halborn performed a combination of manual review of the code 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 smart contracts 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, purpose and use of the platform.
Smart contract manual code review and walkthrough to identify any logic issue.
Thorough assessment of safety and usage of critical Solidity variables and functions in scope that could led to arithmetic related vulnerabilities.
Local testing with custom scripts (Foundry).
Fork testing against main networks (Foundry).
Static analysis of security for scoped contract, and imported functions (Slither).

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)	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:

$E = \prod m_e$

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)	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:

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

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)	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:go-ten

(b) Assessed Commit ID:6cae3418c7b2e48cda56011413a4afd13ddaeb7a

7 files

src

7 files

common

1 file

Structs.sol

solidity

system

5 files

contracts

4 files

Fees.sol

solidity

PublicCallbacks.sol

solidity

SystemDeployer.sol

solidity

TransactionPostProcessor.sol

solidity

utils

1 file

ZenBase.sol

solidity

ten_erc20

1 file

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

#	Title	Severity	Score	Status
HAL-01	Missing validation of callbackId existence in canReattemptCallback modifier	Low	3.1	Solved05/20/2025
HAL-02	Lack of callback cancellation and lifecycle controls	Low	2.5	Solved05/20/2025
HAL-03	Inadequate callback array management	Low	2.3	Partially Solved05/20/2025
HAL-04	Single step ownership transfer process	Low	2.0	Partially Solved05/20/2025
HAL-05	Fixed token minting regardless of transaction value	Low	2.0	Risk Accepted06/11/2025
HAL-06	Lack of transaction processing tracking mechanism	Low	2.0	Risk Accepted06/11/2025
HAL-07	Missing error handling for callbacks	Low	2.0	Risk Accepted06/11/2025
HAL-08	Unnecessary external call in _internalRefund when refund amount is zero	Informational	1.7	Acknowledged06/11/2025
HAL-09	Missing input validation	Informational	1.5	Partially Solved05/20/2025
HAL-10	Use of low-level transfer method	Informational	1.0	Solved05/20/2025
HAL-11	Floating pragma	Informational	1.0	Acknowledged06/11/2025
HAL-12	Use of revert strings instead of custom errors	Informational	0.8	Acknowledged06/11/2025
HAL-13	Unhandled return value in _payForCallback Function	Informational	0.8	Acknowledged06/11/2025
HAL-14	Missing events	Informational	0.6	Solved05/20/2025
HAL-15	Open To-Dos	Informational	0.4	Partially Solved05/20/2025
HAL-16	Redundant default value assignment	Informational	0.3	Solved05/20/2025
HAL-17	Public functions can be marked external	Informational	0.3	Solved05/20/2025
HAL-18	Commented functionality	Informational	0.2	Partially Solved05/20/2025
HAL-19	Missing variable visibility	Informational	0.2	Solved05/20/2025
HAL-20	Lack of named mappings	Informational	0.1	Solved05/20/2025
HAL-21	Unused import	Informational	0.0	Solved05/20/2025
HAL-22	Unoptimized for loops	Informational	0.0	Solved05/20/2025

Disclaimer#

Disclaimer#

Ten Protocol

Obscu/TEN

Ten Protocol

Summary

Introduction#

Assessment Summary#

Test Approach and Methodology#

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:

Scope#

Assessment Summary & Findings Overview#

Findings & Tech Details#

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