Ripple - Batch - Smart Contract Assessment Audit | Ripple

Summary

100% of all REPORTED Findings have been addressed

About this report

Assessment Type

Assurance Assessment

Date of Engagement

January 31st, 2025 - February 13th, 2025

Source Code

rippled

Assessed Commit ID

e213b6c

Severity Breakdown

0Risk Accepted
1Future Release
4Solved
5All Findings

Critical2
- 2Solved
High0
Medium0
Low2
- 1Solved
- 1F. Release
Informational1
- 1Solved

Introduction#

Ripple engaged Halborn to conduct a security assessment on XRP Ledger (XRPL) feature amendments beginning on Jan 31, 2025 and ending on Feb 13, 2025, focusing on PR #5060. The feature introduces a new transaction type Batch that enables atomic execution of multiple transactions, supporting various modes of operation including all-or-nothing, only-one, until-failure, and independent execution patterns.

Assessment Summary#

The team at Halborn assigned a full-time security engineer to assess the security of the node. The security engineer is a blockchain and smart-contract security expert in advanced penetration testing, smart-contract hacking, and deep knowledge of multiple blockchain protocols.

The scope of this audit encompasses:

The new Batch transaction type and its fields
Multi-account transaction signing mechanisms
Inner transaction security controls
Fee calculation and processing
Transaction integrity and atomicity guarantees

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 the Batch Transaction feature security assessment. The following phases and tools were used:

Research into the architecture, purpose, and use of the Batch Transaction feature through extensive documentation review.
Manual code review and walkthrough to identify potential logic issues in transaction processing and security controls.
Security control testing for signature verification, fee processing, and atomic execution guarantees.
Implementation verification of inner transaction controls and batch mode operations.
Trust model validation for both single-account and multi-account transaction scenarios.
Documentation analysis covering security considerations and implementation guidelines.
Functional testing of transaction processing flows and error handling mechanisms.
Edge case testing for complex transaction scenarios and failure modes.
Review of error handling and recovery mechanisms.

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:rippled

(b) Assessed Commit ID:e213b6c0eacdcce3a7662a32163345d52a7d8635

18 files

include / xrpl / protocol

13 files

detail

3 files

features.macro

sfields.macro

transactions.macro

Batch.h

Feature.h

HashPrefix.h

jss.h

Protocol.h

STTx.h

TER.h

c2c2d2ebc5421e410e005974e6b404af672fadee bbc88efaf0d755ddc095e95b3ca14cec7fe45e06 85758f8d14a80874ab984093acf0bbc250fb2b68 https://github.com/XRPLF/rippled/pull/5330

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

Assessment Summary & Findings Overview#

#	Title	Severity	Score	Status
HAL-01	Fee Manipulation in Batch Transaction	Critical	10.0	Solved
HAL-02	Unbounded Resource Consumption in Fee Calculation	Critical	9.4	Solved03/10/2025
HAL-03	Missing sequence number enforcement in preflight	Low	2.5	Solved03/10/2025
HAL-04	Missing OnBehalfOf Transactions Check	Low	2.5	Future Release03/10/2025
HAL-05	Integer Overflow	Informational	0.0	Solved03/10/2025

Findings & Tech Details#

HAL-01Solved

Fee Manipulation in Batch Transaction

Critical

10.0AO:A/AC:L/AX:L/R:N/S:U/C:N/A:M/I:N/D:N/Y:CAO:A/AC:L/AX:L/R:N/S:U/C:N/A:M/I:N/D:N/Y:C

Description

Proof of Concept

Recommendation

Remediation Comment

Addressed in:

c2c2d2ebc5421e410e005974e6b404af672fadee

HAL-02Solved

Unbounded Resource Consumption in Fee Calculation

Critical

9.4AO:A/AC:L/AX:L/R:N/S:C/C:N/A:H/I:N/D:N/Y:NAO:A/AC:L/AX:L/R:N/S:C/C:N/A:H/I:N/D:N/Y:N

Description

Proof of Concept

Recommendation

Remediation Comment

Addressed in:

bbc88efaf0d755ddc095e95b3ca14cec7fe45e06

HAL-03Solved

Missing sequence number enforcement in preflight

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:

85758f8d14a80874ab984093acf0bbc250fb2b68

HAL-04Future Release

Missing OnBehalfOf Transactions Check

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

Remediation Comment

HAL-05Solved

Integer Overflow

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

Addressed in:

https://github.com/XRPLF/rippled/pull/5330

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.