Chromium Browser Extension - ZKPass


Prepared by:

Halborn Logo

HALBORN

Last Updated Unknown date

Date of Engagement: August 27th, 2024 - September 10th, 2024

Summary

100% of all REPORTED Findings have been addressed

All findings

9

Critical

0

High

0

Medium

0

Low

0

Informational

9


1. Introduction

zkPass engaged Halborn to conduct a security assessment on their Transgate extension, beginning on 2024-08-27 and ending on 2024-09-10. The security assessment was scoped to the assets provided to the Halborn team.

2. Assessment Summary

The team at Halborn was provided two weeks for the engagement and assigned a full-time security engineer to verify the security of all the applications. The security engineer is a penetration testing expert with advanced knowledge in web, recon, discovery & infrastructure penetration testing and blockchain protocols.

- Improve the security of the implementation

- Identify potential security issues that could be affecting the implementation

During the security assessment of the extension, several vulnerabilities were identified, posing significant risks to the application’s security posture. However, these vulnerabilities have been mostly remediated through specific actions taken, such as patching, code refactoring, or security best practices from the zkPass team.

Key issues included improper input validation, excessive logging of sensitive data, and the use of outdated cryptographic practices. Input handling functions were found to inadequately sanitize user inputs, which could allow attackers to exploit injection vulnerabilities, leading to data compromise or unauthorized access. Sensitive information, including requests and responses, was logged without redaction, exposing the extension to potential data leaks.

Additionally, the use of outdated dependencies presents a major security concern, as these packages may contain known vulnerabilities that have been publicly disclosed. Furthermore, the application relies on TLS 1.2 for secure communication, which, while still supported, lacks the security enhancements provided by TLS 1.3, such as forward secrecy and reduced handshake latency. The absence of encryption for stored session data and the presence of hardcoded sensitive information further exacerbate the risks.

Addressing these vulnerabilities through package updates, implementation of secure coding practices, and adopting modern security protocols will significantly improve the extension's overall security, reducing the likelihood of exploitation and ensuring better protection of user data.

The browser extension is designed with stringent encryption standards, ensuring that all functions and transmitted data are securely protected. No risks to client data privacy were identified in our assessment, confirming that the extension maintains robust safeguards without compromising client information.


3. 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.

3.1 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 (mem_e)METRIC VALUENUMERICAL VALUE
Attack Origin (AO)Arbitrary (AO:A)
Specific (AO:S)
1
0.2
Attack Cost (AC)Low (AC:L)
Medium (AC:M)
High (AC:H)
1
0.67
0.33
Attack Complexity (AX)Low (AX:L)
Medium (AX:M)
High (AX:H)
1
0.67
0.33
Exploitability EE is calculated using the following formula:

E=meE = \prod m_e

3.2 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 (mIm_I)METRIC VALUENUMERICAL VALUE
Confidentiality (C)None (C:N)
Low (C:L)
Medium (C:M)
High (C:H)
Critical (C:C)
0
0.25
0.5
0.75
1
Integrity (I)None (I:N)
Low (I:L)
Medium (I:M)
High (I:H)
Critical (I:C)
0
0.25
0.5
0.75
1
Availability (A)None (A:N)
Low (A:L)
Medium (A:M)
High (A:H)
Critical (A:C)
0
0.25
0.5
0.75
1
Deposit (D)None (D:N)
Low (D:L)
Medium (D:M)
High (D:H)
Critical (D:C)
0
0.25
0.5
0.75
1
Yield (Y)None (Y:N)
Low (Y:L)
Medium (Y:M)
High (Y:H)
Critical (Y:C)
0
0.25
0.5
0.75
1
Impact II is calculated using the following formula:

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

3.3 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 (CC)COEFFICIENT VALUENUMERICAL VALUE
Reversibility (rr)None (R:N)
Partial (R:P)
Full (R:F)
1
0.5
0.25
Scope (ss)Changed (S:C)
Unchanged (S:U)
1.25
1
Severity Coefficient CC is obtained by the following product:

C=rsC = rs

The Vulnerability Severity Score SS is obtained by:

S=min(10,EIC10)S = min(10, EIC * 10)

The score is rounded up to 1 decimal places.
SeverityScore Value Range
Critical9 - 10
High7 - 8.9
Medium4.5 - 6.9
Low2 - 4.4
Informational0 - 1.9

4. SCOPE

REPOSITORY
(a) Repository: Transgate-extension
(b) Assessed Commit ID: -
(c) Items in scope:
  • Transgate-extension-main/TransGate/asset-manifest.json
  • Transgate-extension-main/TransGate/ba20a8bed0ccb80b0fe4.wasm
  • Transgate-extension-main/TransGate/index.html
↓ Expand ↓
Out-of-Scope: New features/implementations after the remediation commit IDs.

5. Assessment Summary & Findings Overview

Critical

0

High

0

Medium

0

Low

0

Informational

9

Security analysisRisk levelRemediation Date
Improper Input Handling and ParsingInformationalSolved - 10/01/2024
Excessive Logging of Sensitive DataInformationalSolved - 10/01/2024
Potential Weakness in Key ManagementInformationalSolved - 10/01/2024
Lack of Encryption for Stored Session DataInformationalRisk Accepted - 10/01/2024
Lack of Validation in Event ListenersInformationalSolved - 10/01/2024
Lack of Validation When Parsing JSONInformationalRisk Accepted - 10/01/2024
Unvalidated URL ManipulationInformationalSolved - 10/01/2024
Outdated packagesInformationalRisk Accepted - 10/01/2024
Use of TLS1.2InformationalFuture Release - 10/01/2024

6. Findings & Tech Details

6.1 Improper Input Handling and Parsing

//

Informational

Description

Improper input handling occurs when user-supplied data is not properly validated, sanitized, or escaped before being processed. This can lead to injection attacks, data corruption, or application behavior manipulation.

In the apiHelper.ts file, the function pickQueryParams parsed user input directly without validation or sanitization. This made it vulnerable to URL parameter manipulation and injection attacks.

Proof of Concept
function pickQueryParams(paramsStr: string) {
  const params: any[] = []
  if (paramsStr) {
    paramsStr.split("&").forEach((str) => {
      const entry = str.split("=")
      params.push(entry)
    })
  }
  return params
}
Score
(0.0)
Recommendation

Implement strict input validation and sanitation on all user-supplied data. Avoid directly splitting user input and always sanitize before processing.

Remediation Comment

SOLVED: The zkPass team added signature verification for the schema information.

6.2 Excessive Logging of Sensitive Data

//

Informational

Description

Logging sensitive information such as passwords, tokens, or request details can lead to information leakage, especially if logs are exposed to unauthorized users or external systems.

In httpSession.ts, sensitive data such as request objects were logged without redaction, increasing the risk of data exposure.

Proof of Concept
export default async function TPT(props: TPTProps) {
  const { nodeInfo, requests, condition, clientMsgEncKey, nodeMsgDecKey } = props

  const allResponse: any[] = []
  let attrIndexArr: number[] = []
  const publicFields: any[] = []
  const result: ResponseVerifyInfo[] = []
  const privateDataList: any = []
  let i = 0
  while (i < requests.length) {
    console.log('******************START SEND REQUEST*************************')
    const request = requests[i]
    const api = condition.APIs[i]
    const requestInfo = buildRequestInfo(api, request.header, request.body, allResponse)
    const tls = new TlsClient(requestInfo.host)
    tls.setServerNodeInfo(nodeInfo.host, nodeInfo.tid, clientMsgEncKey, nodeMsgDecKey)
    const res: any = await tls.send(requestInfo.text, requestInfo.accept)
    console.log('tls response info', res)
    checkResponseStatus(res.responseStatus)
    if (res.accept?.indexOf('application/json') > -1 && api.assert) {
      const { indexArr, assert } = formatAssertAndCheckValue(res.json, {
        assert: api.assert,
        HRCondition: condition.HRCondition,
      })
      api.assert = assert
      attrIndexArr = attrIndexArr.concat(indexArr)
    }
Score
(0.0)
Recommendation

Avoid logging sensitive data, or ensure that logs are securely stored, and sensitive information is redacted or encrypted before logging.

Remediation Comment

SOLVED: The zkPass team reduced significantly the number of output logs on the console, keeping some of them until they have a final stable version of the code.

6.3 Potential Weakness in Key Management

//

Informational

Description

Poor key management, such as failing to validate key lengths or integrity, can lead to insecure cryptographic operations, exposing the application to brute-force attacks or misuse of weak keys.

In salsa.js, cryptographic keys were used without validation of their length or integrity, increasing the risk of weak key usage.

Proof of Concept
export function Salsa20(key, data){
  // sigma is Salsa's constant "expand 32-byte k"
  const sigma = new Uint8Array([ 101, 120, 112, 97, 110, 100, 32, 51, 50, 45, 98, 121, 116, 101, 32, 107 ])
  const out = new Uint8Array(16)
  core_salsa20(out, data, key, sigma)
  return out
Score
(0.0)
Recommendation

Implement key length validation and ensure proper key management practices. Use libraries that handle key validation and provide secure key exchange mechanisms.

Remediation Comment

SOLVED: The zkPass team removed the vulnerable code from the code.

6.4 Lack of Encryption for Stored Session Data

//

Informational

Description

Storing sensitive information, such as session data, without encryption can expose it to unauthorized access if the storage mechanism is compromised.

In storage.ts, session data was stored in chrome.storage.session without encryption, which could expose user session data to potential theft or modification.

Proof of Concept
export async function setSessionStorage(keyMap: any) {
  return await chrome.storage.session.set(keyMap)
}
Score
(0.0)
Recommendation

Always encrypt sensitive data before storing it, even in browser storage, to prevent unauthorized access.

Remediation Comment

RISK ACCEPTED: The zkPass team stated: "As for the issue mentioned in 6.4, we carefully reviewed it and found that we are only saving the program’s running state and intermediate processes, without involving any user privacy data (the source data is public), so we did not perform encryption."

6.5 Lack of Validation in Event Listeners

//

Informational

Description

Failing to validate or sanitize data before handling it in event listeners can expose applications to malicious inputs or unwanted behavior through injection attacks.

In listeners.ts, incoming messages were handled without validation, leaving the application vulnerable to malicious messages that could manipulate internal states.

Proof of Concept
chrome.runtime.onMessage.addListener(async (request) => {
  if (!request) {
    return
  }
  dispatchEvent(request)
  return true
})
Score
(0.0)
Recommendation

Implement strict validation and sanitation for all incoming event messages, especially those originating from external or user-controlled sources.

Remediation Comment

SOLVED: The zkPass team solved the issue by adding a function to sanitize the request object before performing any operation on the object.

6.6 Lack of Validation When Parsing JSON

//

Informational

Description

Parsing JSON without validation can lead to the processing of malicious or malformed data, which may result in injection attacks or unexpected behavior.

In jsonParse.ts, JSON data from responses were parsed without validation, making the application vulnerable to manipulation through malicious JSON inputs.

Proof of Concept
function genNodeParams(response: TlsResponse, api: API) {
  console.log('-----genNodeParams-----')
  const { records, fullResponse, responseSliceList, requestInfo, accept } = response

  const resStruct = genDataStruct(responseSliceList, api, accept)

  console.log('-----response struct-----', resStruct)
  console.log('-----records-----', records)
  console.log('-----record length-----', records.length)
Score
(0.0)
Recommendation

Implement validation and sanitization checks when parsing JSON data, especially when working with untrusted input or external sources.

Remediation Comment

RISK ACCEPTED: The zkPass team stated: "Since our JSON properties and structure are not fixed, we only validated the JSON’s legality."

6.7 Unvalidated URL Manipulation

//

Informational

Description

Manipulating URLs without proper validation or sanitation can lead to security issues such as URL injection, redirection attacks, or request forgery.

In request.ts, URLs were split and manipulated without validation, which could be exploited for URL injection or improper URL handling.

Proof of Concept
export function buildRequestInfo(api: API, header: any, body: any, dependResponse: any[]): RequestInfo {
  let { url, requestHeaders } = header
  const { method } = header
  const { requestBody } = body
  const verifyFieldPosition: any = {}
  console.log("dependResponse-------", dependResponse)
  console.log("header url-------", url)
  const host = api.host || url.split("/").slice(2, 3)[0]
  url = '/' + url.split("/").slice(3).join("/")
  const end = url.indexOf("?") > -1 ? url.indexOf("?") : url.length

  let query = pickQueryParams(url.substring(end + 1))

  url = url.substring(0, end)
Score
(0.0)
Recommendation

Ensure proper validation and sanitization of URLs before performing operations on them to prevent injection or manipulation attacks.

Remediation Comment

SOLVED: The zkPass team added a signature verification during the execution, and added as an extra layer of security URL's validation.

6.8 Outdated packages

//

Informational

Description

Multiple outdated packages were identified in the extension, which could significantly increase the risk of security vulnerabilities. These outdated dependencies may contain known security flaws that have been publicly disclosed, leaving the extension vulnerable to a variety of potential attacks. Exploiting these vulnerabilities could lead to issues such as unauthorized access, data breaches, or even complete compromise of the system. By continuing to use outdated packages, the extension may miss out on critical security patches and performance improvements provided by more recent versions, thereby increasing the overall attack surface of the application.

Proof of Concept

Issue

Package                       

Patched version

protobufjs Prototype Pollution vulnerability 

protobufjs

>=7.2.5

PostCSS line return parsing error                            

 postcss                                                      

>=8.4.31

 @adobe/css-tools Regular Expression Denial of Service        

 @adobe/css-tools                                             

>=4.3.1

 @adobe/css-tools Improper Input Validation and Inefficient   

 @adobe/css-tools                                             

>=4.3.2

 Follow Redirects improperly handles URLs in the url.parse()  

 follow-redirects                                             

>=1.15.4

 follow-redirects' Proxy-Authorization header kept across     

 follow-redirects                                             

>=1.15.6

 browserify-sign upper bound check issue in dsaVerify leads 

 browserify-sign                                              

>=4.2.2

 Path traversal in webpack-dev-middleware                     

 webpack-dev-middleware                                       

>=5.3.4

 Express.js Open Redirect in malformed URLs                   

 express                                                      

>=4.19.2

 express vulnerable to XSS via response.redirect()            

 express                                                      

>=4.20.0

 Babel vulnerable to arbitrary code execution when compiling  

 @babel/traverse                                              

>=7.23.2

 Axios Cross-Site Request Forgery Vulnerability               

 axios                                                        

>=1.6.0

 Server-Side Request Forgery in axios                         

 axios                                                        

>=1.7.4

 Uncontrolled resource consumption in braces                  

 braces                                                       

>=3.0.3

 ejs lacks certain pollution protection                       

 ejs                                                          

>=3.1.10

 ws affected by a DoS when handling a request with many HTTP  

 ws                                                           

>=8.17.1

 Regular Expression Denial of Service (ReDoS) in micromatch   

 micromatch                                                   

>=4.0.8

 Webpack's AutoPublicPathRuntimeModule has a DOM Clobbering   

 webpack                                                      

>=5.94.0

 body-parser vulnerable to denial of service when url         

 body-parser                                                  

>=1.20.3

 send vulnerable to template injection that can lead to XSS   

 send                                                         

>=0.19.0

 serve-static vulnerable to template injection that can lead  

 serve-static                                                 

>=1.16.0

 path-to-regexp outputs backtracking regular expressions      

 path-to-regexp                                               

>=0.1.10

 Regular Expression Denial of Service in content              

 content                                                      

>=3.0.7

 Inefficient Regular Expression Complexity in nth-check       

 nth-check                                                    

>=2.0.1

 ws affected by a DoS when handling a request with many HTTP  

 ws                                                           

>=7.5.10

Elliptic allows BER-encoded signatures    

 elliptic                                                     

>=6.5.7

Elliptic's ECDSA missing check for whether leading bit of r and s is zero

 elliptic                                                     

>=6.5.7

Elliptic's EDDSA missing signature length check

 elliptic                                                     

>=6.5.7

Score
(0.0)
Recommendation

Ensure that all dependencies are updated to the latest stable versions. Use your package manager to check for available updates and apply them. Regular updates would ensure that your extension benefits from the latest security patches and performance improvements.

Remediation Comment

RISK ACCEPTED: The zkPass team stated: "During the upgrade process, we discovered a large number of package incompatibilities, so we have decided not to proceed with the upgrade for now."

6.9 Use of TLS1.2

//

Informational

Description

TLS 1.2 is still secure but lacks some security enhancements and optimizations of TLS 1.3, including better encryption methods, forward secrecy, and reduced latency.

Proof of Concept
export default class TlsClient {
  constructor(host, tls_version = TLS_VERSION.TLS_1_2) {
    this.handshake_messages = new Buffer()
    this.tls_version = tls_version
    this.host = host
    this.params = new HandshakeParameters()
    this.records = []
    this.appData = ''
    this.appDataLen = -3
    this.acceptType = ''
Score
(0.0)
Recommendation

Upgrade to TLS 1.3 to benefit from stronger encryption, forward secrecy, and reduced handshake latency. If TLS 1.2 must be used, ensure that only secure ciphers are enabled (e.g., AES-GCM or ChaCha20-Poly1305) and that weaker algorithms (like RSA key exchange) are disabled.

Remediation Comment

PENDING: The zkPass team stated: "For the support of TLS 1.3 mentioned in 6.9, it is included in our future development plans and will not be handled in the current version."

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.

© Halborn 2025. All rights reserved.