CVE-2025-26708

Executive Summary

CVE-2025-26708 is a configuration defect vulnerability in ZTELink 5.4.9 for iOS. The flaw resides in the WiFi parameter configuration of the ZTELink application, allowing an attacker to obtain unauthorized access to the WiFi service. This vulnerability is classified as a configuration defect (CWE-16) and has a low CVSS score of 4.2 due to the local attack vector and limited impact on confidentiality. No public proof-of-concept (PoC) or exploit code is currently available, and the vendor (ZTE) has not released a patch. The EPSS score of 0.0% indicates a very low probability of exploitation in the wild.

Supply Chain & Package Security

This vulnerability is specific to the ZTELink iOS application, which is not distributed via NPM, PyPI, Go, or Ruby package managers. Therefore, supply chain security considerations are limited to the iOS App Store distribution channel. Users should verify the integrity of the application by checking its digital signature and ensuring it is downloaded from the official App Store.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Base Score: 4.2 (Medium)
• Attack Vector (AV): Local (L) – The attacker must have physical or logical access to the device.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – The vulnerable component and the impacted component are the same.
• Confidentiality (C): Low (L) – Limited information disclosure (WiFi credentials).
• Integrity (I): None (N) – No data modification.
• Availability (A): None (N) – No impact on availability.

Threat Level: Low to Medium. The vulnerability requires local access to the device, but no privileges or user interaction. An attacker could extract WiFi credentials from the ZTELink configuration.

Deep Dive & Mechanics

The vulnerability is rooted in how ZTELink 5.4.9 for iOS stores and manages WiFi parameters. The application likely stores WiFi credentials (SSID and password) in a configuration file or plist that is not properly protected. An attacker with access to the device (e.g., via a malicious app or physical access) can read this configuration data and gain unauthorized access to the WiFi network.

Root Cause: Insecure storage of WiFi credentials in the application’s configuration files. The application does not use iOS Keychain or other secure storage mechanisms.

Attack Vector: Local access to the iOS device. This could be achieved through:

• A malicious app running on the same device.
• Physical access to an unlocked device.
• Exploitation of another vulnerability to gain local access.

Impact: Unauthorized access to the WiFi network, potentially leading to further network-based attacks.

Vulnerable vs. Patched Code

Since no patch is available, a comparison cannot be made. However, a secure implementation would use the iOS Keychain to store WiFi credentials. Below is an example of vulnerable and patched code patterns.

Vulnerable Code (Objective-C):

// Vulnerable: Storing WiFi password in NSUserDefaults
NSString *wifiPassword = @"my_secret_password";
[[NSUserDefaults standardUserDefaults] setObject:wifiPassword forKey:@"ZTELinkWiFiPassword"];
[[NSUserDefaults standardUserDefaults] synchronize];

Patched Code (Objective-C):

// Patched: Using iOS Keychain
NSString *wifiPassword = @"my_secret_password";
NSData *passwordData = [wifiPassword dataUsingEncoding:NSUTF8StringEncoding];
NSMutableDictionary *query = [NSMutableDictionary dictionary];
[query setObject:(__bridge id)kSecClassGenericPassword forKey:(__bridge id)kSecClass];
[query setObject:@"ZTELinkWiFiPassword" forKey:(__bridge id)kSecAttrService];
[query setObject:passwordData forKey:(__bridge id)kSecValueData];
SecItemAdd((__bridge CFDictionaryRef)query, NULL);

Exploitation & Lab Setup

Red Team

Prerequisites:

• iOS device with ZTELink 5.4.9 installed.
• Local access to the device (e.g., via a malicious app or physical access).

Exploitation Steps:

1. Gain local access to the iOS device.
2. Locate the ZTELink configuration file (typically in the app’s Documents or Library directory).
3. Extract the WiFi credentials from the configuration file.
4. Use the credentials to connect to the WiFi network.

Example Command (using a jailbroken device):

# Access the app's sandbox
cd /var/mobile/Containers/Data/Application/<UUID>/Library/Preferences/
# Read the plist file
plutil -p com.zte.ztelink.plist

Blue Team

Detection:

• Monitor for unauthorized access to the ZTELink app’s sandbox.
• Use endpoint detection and response (EDR) tools to detect file reads from the app’s configuration directory.
• Alert on any process reading the ZTELink plist file.

Mitigation:

• Ensure the device is locked and not left unattended.
• Use mobile device management (MDM) to enforce secure configurations.
• Apply the principle of least privilege to apps.

Indicators of Compromise (IOCs)

• File Path: /var/mobile/Containers/Data/Application/<UUID>/Library/Preferences/com.zte.ztelink.plist
• Process: Any process reading the above file.
• Network: Unauthorized WiFi connections using credentials extracted from the device.

Detection Engineering

YARA Rule

rule CVE_2025_26708_ZTELink_WiFi_Config {
    meta:
        description = "Detects ZTELink WiFi configuration file access"
        author = "Valters IT"
        date = "2025-03-20"
        reference = "CVE-2025-26708"
    strings:
        $plist = "com.zte.ztelink.plist"
        $wifi = "WiFiPassword"
    condition:
        $plist or $wifi
}

Sigma Rule

title: ZTELink WiFi Configuration Access
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects access to ZTELink WiFi configuration file
author: Valters IT
date: 2025/03/20
references:
    - CVE-2025-26708
logsource:
    category: file_event
    product: macos
detection:
    selection:
        TargetFilename|contains: 'com.zte.ztelink.plist'
    condition: selection
falsepositives:
    - Legitimate ZTELink app access
level: medium

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-26708 ZTELink WiFi Credential Exfiltration"; flow:to_server,established; content:"ZTELink"; content:"WiFiPassword"; distance:0; within:100; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Update ZTELink: Check the App Store for updates. If no patch is available, consider removing the app.
2. Secure Device: Ensure the iOS device is locked with a strong passcode and not left unattended.
3. Monitor: Use MDM or EDR to detect unauthorized access to app sandboxes.

Long-Term Fix:

• ZTE must release a patched version that uses iOS Keychain for credential storage.
• Users should apply the patch as soon as it becomes available.

Workaround:

• Manually enter WiFi credentials each time instead of storing them in ZTELink.
• Use a separate, secure password manager.

Valters IT