CVE-2025-26707

Executive Summary

CVE-2025-26707 is a privilege escalation vulnerability in ZTE GoldenDB, a distributed database product. The vulnerability stems from improper privilege management, allowing an authenticated attacker with low privileges to escalate their privileges within the database system. This could lead to unauthorized data access, modification, or disruption of database operations. The vulnerability affects versions 6.1.03 through 6.1.03.05. As of this report, no official patch has been released, and no public proof-of-concept (PoC) code is available. The EPSS score is 0.0%, indicating a very low probability of exploitation in the wild at this time.

CVSS Breakdown & Threat Level

• CVSS Score: 5.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
• Attack Vector (AV): Network (N) - The vulnerability can be exploited remotely over the network.
• Attack Complexity (AC): Low (L) - No special conditions are required for exploitation.
• Privileges Required (PR): Low (L) - The attacker must have valid low-privileged credentials.
• User Interaction (UI): None (N) - No user interaction is required.
• Scope (S): Unchanged (U) - The vulnerability does not affect resources beyond the database.
• Confidentiality (C): Low (L) - Limited unauthorized data access is possible.
• Integrity (I): Low (L) - Limited unauthorized data modification is possible.
• Availability (A): Low (L) - Limited impact on database availability.

Threat Level: Medium. While the CVSS score is moderate, the lack of a patch and the potential for privilege escalation within a critical database system warrants attention.

Deep Dive & Mechanics

The vulnerability is rooted in improper privilege management within ZTE GoldenDB. The database likely uses a role-based access control (RBAC) system where different users have different privileges. The flaw allows a user with low privileges (e.g., a regular database user) to escalate their privileges to a higher level (e.g., database administrator). This could be achieved through:

• Exploiting a flaw in stored procedures or functions: The database might have stored procedures that run with elevated privileges. If these procedures do not properly validate the caller's privileges, a low-privileged user could invoke them to perform privileged actions.
• Manipulating privilege tables: The attacker might be able to directly modify internal database tables that store user privileges, bypassing the intended RBAC controls.
• Abusing a misconfiguration in the authentication/authorization module: The database might have a flaw in how it checks user privileges, allowing a user to impersonate another user or assume a higher privilege level.

The exact mechanism is not publicly disclosed, but the core issue is that the database fails to enforce proper privilege separation.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, the following hypothetical example illustrates the type of flaw that could exist:

Vulnerable Code (Hypothetical Stored Procedure):

CREATE PROCEDURE `admin_backup`()
BEGIN
    -- This procedure runs with root privileges
    -- It does not check if the caller has admin rights
    EXECUTE IMMEDIATE 'BACKUP DATABASE ...';
END;

Patched Code (Hypothetical):

CREATE PROCEDURE `admin_backup`()
BEGIN
    -- Check if the caller has the 'ADMIN' role
    IF (SELECT COUNT(*) FROM user_roles WHERE user = CURRENT_USER() AND role = 'ADMIN') > 0 THEN
        EXECUTE IMMEDIATE 'BACKUP DATABASE ...';
    ELSE
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'Insufficient privileges';
    END IF;
END;

Exploitation & Lab Setup

Red Team

Objective: Escalate privileges from a low-privileged database user to an administrator.

Prerequisites:

• Access to a ZTE GoldenDB instance (version 6.1.03 to 6.1.03.05).
• Valid low-privileged database credentials (e.g., username: user1, password: password1).

Steps:

1. Connect to the database:

   mysql -h <target_ip> -u user1 -p
   

2. Enumerate available stored procedures:

   SHOW PROCEDURE STATUS;
   

3. Identify a privileged procedure that lacks proper access controls. For example, a procedure named escalate_privileges or admin_backup.

4. Execute the privileged procedure:

   CALL admin_backup();
   

5. If successful, attempt to create a new admin user or grant yourself admin privileges:

   CREATE USER 'hacker'@'%' IDENTIFIED BY 'hacker123';
   GRANT ALL PRIVILEGES ON *.* TO 'hacker'@'%' WITH GRANT OPTION;
   

6. Verify escalated privileges:

   SHOW GRANTS;
   

Blue Team

Objective: Detect and prevent privilege escalation attempts.

Detection:

• Monitor database logs for unusual execution of stored procedures by low-privileged users.
• Alert on CREATE USER or GRANT statements executed by non-admin users.
• Monitor for failed privilege checks (e.g., SIGNAL SQLSTATE '45000' errors).

Prevention:

• Apply the principle of least privilege. Ensure that stored procedures that perform privileged actions explicitly check the caller's privileges.
• Regularly audit user roles and permissions.
• Implement database activity monitoring (DAM) solutions.
• If possible, restrict network access to the database to only trusted hosts.

Indicators of Compromise (IOCs)

• Log Entries:
  • Successful execution of privileged stored procedures by low-privileged users.
  • CREATE USER or GRANT statements executed by non-admin users.
  • Multiple failed login attempts followed by successful privilege escalation.
• Network Traffic:
  • Unusual database queries from unexpected IP addresses.
• System Changes:
  • New database users with elevated privileges.
  • Modified privilege tables.

Detection Engineering

YARA Rule

rule CVE_2025_26707_Privilege_Escalation {
    meta:
        description = "Detects potential privilege escalation attempts in ZTE GoldenDB logs"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-26707"
    strings:
        $s1 = "CALL " ascii wide nocase
        $s2 = "GRANT ALL" ascii wide nocase
        $s3 = "CREATE USER" ascii wide nocase
        $s4 = "user1" ascii wide nocase  // Example low-privileged user
    condition:
        any of ($s1, $s2, $s3) and $s4
}

Sigma Rule

title: ZTE GoldenDB Privilege Escalation Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects potential privilege escalation attempts in ZTE GoldenDB logs
author: Valters IT
date: 2025-04-10
logsource:
    product: zte
    service: goldendb
detection:
    selection:
        EventID: 1  // Example event ID for database query
        Query|contains:
            - 'CALL '
            - 'GRANT ALL'
            - 'CREATE USER'
    condition: selection
falsepositives:
    - Legitimate administrative actions
level: high

Suricata Rule

alert tcp $EXTERNAL_NET any -> $HOME_NET 3306 (msg:"CVE-2025-26707 ZTE GoldenDB Privilege Escalation Attempt"; flow:to_server,established; content:"CALL "; nocase; content:"GRANT ALL"; nocase; distance:0; within:100; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate affected systems: If possible, restrict network access to the ZTE GoldenDB instances to only trusted hosts.
2. Review user privileges: Audit all database users and ensure they have the minimum necessary privileges.
3. Monitor logs: Enable detailed logging and monitor for suspicious activity as described in the IOCs and Detection Engineering sections.

Long-Term Fix:

• Apply the official patch when released by ZTE. Monitor ZTE's security advisories for updates.
• Upgrade to a patched version once available.
• Implement strict RBAC: Ensure all stored procedures and functions that perform privileged actions explicitly check the caller's privileges.
• Conduct a security audit of the database configuration and code.

Workarounds (if patching is not immediately possible):

• Disable or restrict access to privileged stored procedures that are not essential.
• Implement a Web Application Firewall (WAF) or database firewall to filter malicious queries.
• Use database activity monitoring (DAM) tools to detect and alert on anomalous behavior.

Valters IT