Huma - PR 124 Audit | Huma Finance | Halborn Audit Reports

Summary

100% of all REPORTED Findings have been addressed

About this report

Assessment Type

Assurance Assessment

Date of Engagement

December 27th, 2024 - January 2nd, 2025

Source Code

huma-solana-programs huma-solana-programs huma-solana-programs huma-solana-programs huma-solana-programs huma-solana-programs huma-solana-programs

Assessed Commit ID

7d84086 https://github.com/00labs/huma-solana-programs/pull/113 https://github.com/00labs/huma-solana-programs/pull/118 https://github.com/00labs/huma-solana-programs/pull/120 https://github.com/00labs/huma-solana-programs/pull/119 https://github.com/00labs/huma-solana-programs/pull/123 https://github.com/00labs/huma-solana-programs/pull/124

Severity Breakdown

1Partially Solved
1Not Applicable
6Acknowledged
1Risk Accepted
11Solved
20All Findings

Critical0
High0
Medium0
Low7
- 6Solved
- 1Risk A.
Informational13
- 6Ack.
- 5Solved
- 1N/A
- 1P. Solved

Introduction#

Huma engaged Halborn to conduct a security assessment of the Huma Protocol Solana program from September 9th, 2024, to January 2nd, 2025. Huma Protocol is an on-chain PayFi protocol that provides liquidity to payments financing use cases with an initial focus on business borrowers. It takes a modular approach to support diverse needs of Structured Finance. The protocol can be extended by adding additional modules to key functions such as tranche policies, fee managers, due managers, and calendar.

In December, Huma introduced three incremental features to the protocol:

Monthly interest withdrawals for lenders (LPs)
Ability for the pool owner to make payments on behalf of borrowers
A system account (Sentinel) to automatically trigger redemption requests

Halborn then performed an incremental audit of these new features to ensure the continued security and reliability of the protocol.

Assessment Summary#

Halborn was provided 3.5 weeks for the initial engagement and 6 and 4 days for the additional scope assessments, and assigned two full-time security engineer/s to review the security of the Solana Programs in scope. The engineers are blockchain and smart contract security experts with advanced smart contract hacking skills, and deep knowledge of multiple blockchain protocols.

The purpose of the assessment is to:

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

In summary, Halborn identified some security concerns. The main ones were the following:

Lack of proper validation in Deposit
Incomplete new owner validation in Transfer Ownership process
Possibility to close started Credit with commitment
Lack of pool name length validation
Lack of pool currency code length validation
Receivable can be approved by different pool
Reallocating pools with new format will lead to data inconsistency

Most of the findings were addressed, and the corresponding fixes have been merged into the branches listed below. The final commits reflect the changes that solved the issues:

80799a02665dab07f695e8c9aee03f50b99af26f on develop branch
5da8c0ac3b6899557ba185379bf4eaa8aa9efe17 on main

Test Approach and Methodology#

Halborn performed a combination of a manual review of the source code and automated security testing to balance efficiency, timeliness, practicality, and accuracy in regard to the scope of the program assessment. While manual testing is recommended to uncover flaws in business logic, processes, and implementation; automated testing techniques help enhance coverage of programs 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 the architecture, purpose, and use of the platform.
Manual program source code review to identify business logic issues.
Mapping out possible attack vectors
Thorough assessment of safety and usage of critical Rust variables and functions in scope that could lead to arithmetic vulnerabilities.
Scanning dependencies for known vulnerabilities (
```
cargo audit
```
).
Local runtime testing (
```
anchor-test
```
)

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:huma-solana-programs

(b) Assessed Commit ID:7d840864f4bbd56e0a7b8531c8483bf1ba81c182

Show out-of-scope files (83)

165 files

00labs / huma-solana-programs / blob / audit

82 files

programs

79 files

huma

73 files

src

71 files

common

14 files

calendar

1 file

tests.rs

rust

huma_config

7 files

instructions

5 files

create_huma_config.rs

rust

liquidity_asset.rs

rust

mod.rs

rust

(a) Repository:huma-solana-programs

(b) Assessed Commit ID:https://github.com/00labs/huma-solana-programs/pull/113

Show out-of-scope files (43)

52 files

huma / src

9 files

pool

3 files

instructions

2 files

create_pool.rs

rust

update_pool_config.rs

rust

states.rs

rust

tranche_vault / instructions

4 files

add_redemption_request.rs

rust

cancel_redemption_request.rs

rust

deposit.rs

rust

transfer_hook.rs

rust

tranche-token-hook / src / instructions

1 file

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

(a) Repository:huma-solana-programs

(b) Assessed Commit ID:https://github.com/00labs/huma-solana-programs/pull/118

Show out-of-scope files (1)

5 files

programs / huma / src

4 files

common

1 file

constants.rs

rust

tranche_vault

2 files

instructions

1 file

manage_lender.rs

rust

states.rs

rust

lib.rs

rust

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

(a) Repository:huma-solana-programs

(b) Assessed Commit ID:https://github.com/00labs/huma-solana-programs/pull/120

Show out-of-scope files (1)

7 files

programs / huma / src

6 files

common

2 files

errors.rs

rust

preconditions.rs

rust

tranche_vault

3 files

instructions

2 files

mod.rs

rust

withdraw_yields.rs

rust

mod.rs

rust

lib.rs

rust

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

(a) Repository:huma-solana-programs

(b) Assessed Commit ID:https://github.com/00labs/huma-solana-programs/pull/119

Show out-of-scope files (1)

2 files

programs / huma / src / pool

1 file

epoch_manager.rs

rust

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

(a) Repository:huma-solana-programs

(b) Assessed Commit ID:https://github.com/00labs/huma-solana-programs/pull/123

Show out-of-scope files (1)

2 files

programs / huma / src / tranche_vault / instructions

1 file

withdraw_yields.rs

rust

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

(a) Repository:huma-solana-programs

(b) Assessed Commit ID:https://github.com/00labs/huma-solana-programs/pull/124

Show out-of-scope files (1)

7 files

programs / huma / src

6 files

credit

5 files

instructions

3 files

make_payment_on_behalf_of.rs

rust

make_payment.rs

rust

mod.rs

rust

credit.rs

rust

mod.rs

rust

lib.rs

rust

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

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

Assessment Summary & Findings Overview#

#	Title	Severity	Score	Status
HAL-01	LACK OF PROPER VALIDATION IN DEPOSIT	Low	3.8	Solved09/25/2024
HAL-02	INCOMPLETE NEW OWNER VALIDATION IN THE TRANSFER OWNERSHIP PROCESS	Low	2.6	Risk Accepted
HAL-03	LACK OF POOL NAME LENGTH VALIDATION	Low	2.5	Solved09/25/2024
HAL-04	POSSIBILITY TO CLOSE STARTED CREDIT WITH COMMITMENT	Low	2.5	Solved09/28/2024
HAL-05	RECEIVABLE CAN BE APPROVED BY DIFFERENT POOL	Low	2.5	Solved09/25/2024
HAL-06	LACK OF CURRENCY CODE LENGTH VALIDATION	Low	2.5	Solved09/25/2024
HAL-07	REALLOCATING POOLS WITH NEW FORMAT WILL LEAD TO DATA INCONSISTENCY	Low	2.3	Solved12/02/2024
HAL-08	LACK OF EA AND POOL OWNER TREASURY VALIDATION IN POOL CREATION	Informational	1.8	Acknowledged
HAL-09	LACK OF DELEGATED AMOUNT VALIDATION IN ADD REDEMPTION REQUESTS FOR PREMATURE DEPOSITS	Informational	1.6	Solved12/01/2024
HAL-10	POSSIBILITY OF INCONSISTENT LATE PAYMENT FEES	Informational	1.6	Acknowledged
HAL-11	LACK OF VALIDATION FOR EXTENSIONS OF THE MINT	Informational	1.6	Solved
HAL-12	RELIANCE ON MANUAL PROCESS	Informational	1.6	Acknowledged12/30/2024
HAL-13	POTENTIAL DENIAL OF SERVICE IF POOLS USING NON-REALLOCATED POOLCONFIG WITH THE OLD FORMAT	Informational	1.1	Acknowledged11/28/2024
HAL-14	LACK OF VALIDATION FOR THE MINIMUM BORROW AMOUNT TO EXCEED THE FEES	Informational	0.9	Acknowledged
HAL-15	POTENTIAL COMPLETE PROFIT CAPTURE VIA ADMIN FEES	Informational	0.9	Not Applicable
HAL-16	MONEY MOVEMENT WHEN PROTOCOL IS PAUSED IN SOME INSTRUCTIONS	Informational	0.8	Solved09/27/2024
HAL-17	EA AND POOL OWNER TREASURY WILL ALSO NEED TO APPROVE DELEGATE IF THEY WANT TO CALL DEPOSIT	Informational	0.6	Solved12/01/2024
HAL-18	LACK OF DELEGATE VALIDATION IN MAKE PAYMENT	Informational	0.6	Acknowledged
HAL-19	PASSING SUPERFLUOUS SYSTEM PROGRAM ACCOUNT	Informational	0.0	Solved09/27/2024
HAL-20	INCONSISTENCIES IN DOCUMENTATION	Informational	0.0	Partially Solved09/22/2024

Remediation Comment

8. 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.