Zr-sign Audit | Zenrock Laboratories

Summary

100% of all REPORTED Findings have been addressed

About this report

Assessment Type

Assurance Assessment

Date of Engagement

April 12th, 2024 - April 19th, 2024

Source Code

zr-sign

Assessed Commit ID

6c40093

Severity Breakdown

3Acknowledged
4Risk Accepted
13Solved
20All Findings

Critical0
High0
Medium0
Low8
- 4Solved
- 4Risk A.
Informational12
- 9Solved
- 3Ack.

Introduction#

ZenRockLabs engaged Halborn to conduct a security assessment on their smart contracts beginning on 04-12-2024 and ending on 04-19-2024. The security assessment was scoped to the smart contracts provided in the https://github.com/zenrocklabs/zr-sign GitHub repository. Commit hashes and further details can be found in the Scope section of this report.

Assessment Summary#

Halborn was provided 1 week 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 mostly addressed by the Zenrock Labs team.

The main identified issues were:

Response functions can be called during contract's paused state, allowing to continue contract operations.
Lack of match identification between response function caller and recovered address.
Lack of storage verification allows for duplicated public keys.

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.
Manual testing with custom scripts (Foundry).
Static Analysis of security for scoped contract, and imported functions.

Out-of-scope#

External libraries and financial-related attacks.
New features/implementations after/within the remediation commit IDs.

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:zr-sign

(b) Assessed Commit ID:6c400938b57f9f37d8baa13cca13ddf36791c214

Show out-of-scope files (9)

12 files

contracts

3 files

proxy

1 file

ZrProxy.sol

solidity

2 files

Sign.sol

solidity

ZrSign.sol

solidity

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

Assessment Summary & Findings Overview#

#	Title	Severity	Score	Status
HAL-01	Lack of storage verification allows for duplicated public keys	Low	2.5	Solved05/01/2024
HAL-02	Missing threshold verification for fees	Low	2.5	Risk Accepted
HAL-03	Lack of input validation for destination chain id may allow for requests to invalid chains	Low	2.5	Risk Accepted
HAL-04	Response functions can be called during contract's paused state allowing to continue contract operations	Low	2.5	Solved05/01/2024
HAL-05	Lack of match identification between response functions caller and recovered address	Low	2.5	Risk Accepted
HAL-06	Missing traceId verification in signature resolve function	Low	2.5	Solved05/06/2024
HAL-07	Contract may emit multiple resolving events for the same data	Low	2.5	Solved05/01/2024
HAL-08	Insufficient public key validation	Low	2.5	Risk Accepted
HAL-09	Improper contract naming conventions in upgradeable OpenZeppelin inheritance	Informational	0.0	Solved05/01/2024
HAL-10	Missing namespace NatSpec tag for ERC-7201	Informational	0.0	Solved05/01/2024
HAL-11	PUSH0 is not supported by all chains	Informational	0.0	Solved05/01/2024
HAL-12	Transfer with hardcoded gas amount	Informational	0.0	Solved05/01/2024
HAL-13	Unused `SRC_WALLET_TYPE_ID` constant declaration	Informational	0.0	Acknowledged
HAL-14	Public functions not called within the contract can be made external	Informational	0.0	Acknowledged
HAL-15	Lack of verification for config functions input values	Informational	0.0	Acknowledged
HAL-16	Unnecessary payable modifier in `withdrawFees()`	Informational	0.0	Solved05/01/2024
HAL-17	Typo in function name	Informational	0.0	Solved05/01/2024
HAL-18	Misleading error name	Informational	0.0	Solved05/01/2024
HAL-19	Unnecessary storage access	Informational	0.0	Solved05/01/2024
HAL-20	Missing initialization function for AccessControl	Informational	0.0	Solved05/01/2024

Findings & Tech Details#

HAL-01Solved

Lack of storage verification allows for duplicated public keys

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

Proof of Concept

Recommendation

References

Sign.sol#L437-L469

HAL-02Risk Accepted

Missing threshold verification for fees

Low

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

Description

Recommendation

References

ZrSign.sol#L90-L94
ZrSign.sol#L102-L106

HAL-03Risk Accepted

Lack of input validation for destination chain id may allow for requests to invalid chains

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

References

Sign.sol#L483-L511

HAL-04Solved

Response functions can be called during contract's paused state allowing to continue contract operations

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

Proof of Concept

Recommendation

References

Sign.sol#L145-L149
Sign.sol#L277-L279

HAL-05Risk Accepted

Lack of match identification between response functions caller and recovered address

Low

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

Description

Recommendation

References

Sign.sol#L553-L566

HAL-06Solved

Missing traceId verification in signature resolve function

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

References

Sign.sol#L525-L537

HAL-07Solved

Contract may emit multiple resolving events for the same data

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

Proof of Concept

Recommendation

References

Sign.sol#L525-L537

HAL-08Risk Accepted

Insufficient public key validation

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

References

Sign.sol#L721-L726

HAL-09Solved

Improper contract naming conventions in upgradeable OpenZeppelin inheritance

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

References

Sign.sol#L17

HAL-10Solved

Missing namespace NatSpec tag for ERC-7201

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

References

Sign.sol#L120-L123

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.