CVE-2025-26706

Executive Summary

CVE-2025-26706 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 GoldenDB versions from 6.1.03 through 6.1.03.07. As of this report, no official patch has been released, and no public proof-of-concept (PoC) or exploit 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: 5.4 (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 vulnerable component.
• 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 system availability.

Threat Level: Medium. While the CVSS score is moderate, the potential for privilege escalation in a database system is a serious concern. The lack of a patch and public exploit code reduces the immediate risk, but organizations using affected versions should prioritize mitigation.

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 (e.g., read-only, read-write, admin). The flaw allows a user with low privileges to bypass these controls and gain higher privileges, such as database administrator (DBA) rights.

Technical Details:

• Root Cause: The application fails to properly validate or enforce privilege boundaries when processing certain requests or commands. This could be due to missing authorization checks, insecure direct object references (IDOR), or flawed session management.
• Attack Vector: An authenticated attacker sends specially crafted SQL queries or API calls to the GoldenDB service. These requests are processed with elevated privileges due to the improper privilege management.
• Impact: Once escalated, the attacker can:
  • Read, modify, or delete any data in the database.
  • Create or drop database objects (tables, views, procedures).
  • Potentially execute operating system commands if the database has extended capabilities.
  • Disrupt database availability.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, based on the vulnerability type, the following hypothetical example illustrates the issue:

Vulnerable Code (Hypothetical):

-- Stored procedure that executes a query with the caller's privileges
CREATE PROCEDURE execute_query(@query NVARCHAR(MAX))
AS
BEGIN
    EXEC sp_executesql @query;
END;

In this example, if the procedure does not check the caller's privileges, a low-privileged user could call it to execute privileged commands.

Patched Code (Hypothetical):

-- Patched version with privilege check
CREATE PROCEDURE execute_query(@query NVARCHAR(MAX))
AS
BEGIN
    IF NOT EXISTS (SELECT 1 FROM sys.database_permissions WHERE grantee_principal_id = DATABASE_PRINCIPAL_ID() AND permission_name = 'CONTROL')
    BEGIN
        RAISERROR('Insufficient privileges', 16, 1);
        RETURN;
    END;
    EXEC sp_executesql @query;
END;

The patched version explicitly checks if the caller has the necessary privileges before executing the query.

Exploitation & Lab Setup

Red Team

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

Prerequisites:

• Access to a GoldenDB instance with a low-privileged account (e.g., user1 with read-only access).
• Network connectivity to the database port (default: 3306 for MySQL-compatible, but GoldenDB may use a custom port).

Steps:

1. Reconnaissance: Identify the GoldenDB version and available stored procedures.

   SELECT @@version;
   SHOW PROCEDURE STATUS;
   

2. Identify Vulnerable Functionality: Look for stored procedures or functions that execute dynamic SQL or perform privileged operations without proper checks.
3. Exploit: Craft a request to exploit the privilege escalation. For example, if a procedure run_as_admin exists:

   EXEC run_as_admin 'CREATE USER hacker IDENTIFIED BY ''password''';
   EXEC run_as_admin 'GRANT DBA TO hacker';
   

4. Post-Exploitation: Use the new DBA privileges to exfiltrate data or establish persistence.

Note: Since no public exploit exists, this is a theoretical approach. Actual exploitation would require reverse engineering the specific GoldenDB version.

Blue Team

Objective: Detect and prevent privilege escalation attempts.

Detection:

• Monitor database logs for unusual queries executed by low-privileged users.
• Alert on attempts to execute stored procedures that are typically reserved for administrators.
• Use database activity monitoring (DAM) tools to track privilege changes.

Prevention:

• Apply the principle of least privilege (PoLP) to all database accounts.
• Regularly audit database roles and permissions.
• Implement network segmentation to limit access to the database.
• Enable detailed auditing for all privileged operations.

Honeypot:

• Create a fake high-privilege account and monitor for any login attempts or usage.

Indicators of Compromise (IOCs)

• Network:
  • Unusual SQL queries from low-privileged users attempting to execute administrative commands.
  • Connections to the database from unexpected IP addresses.
• Host:
  • Database logs showing privilege escalation attempts (e.g., GRANT statements from non-admin users).
  • New user accounts created with elevated privileges.
• File:
  • Modified database configuration files (e.g., my.cnf or goldendb.conf).
  • Suspicious files in the database data directory.

Example IOC (Sigma Rule):

title: GoldenDB Privilege Escalation Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects attempts to execute GRANT statements by non-admin users
logsource:
    product: golden_db
    service: audit_log
detection:
    selection:
        EventID: 1234  # Hypothetical event ID for privilege change
        User: "user1"  # Low-privileged user
        Query: "GRANT*"
    condition: selection
falsepositives:
    - Legitimate administrative actions (should be rare)
level: high

Detection Engineering

YARA Rule

rule CVE_2025_26706_GoldenDB_PrivEsc {
    meta:
        description = "Detects privilege escalation attempts in ZTE GoldenDB logs"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-26706"
    strings:
        $priv_esc = /GRANT\s+(ALL|DBA|SYSDBA|SYSOPER)\s+TO/i
        $low_priv_user = /user1|readonly|app_user/i
    condition:
        $priv_esc and $low_priv_user
}

Sigma Rule

title: GoldenDB Privilege Escalation via Improper Privilege Management
id: 87654321-4321-4321-4321-210987654321
status: experimental
description: Detects privilege escalation attempts in ZTE GoldenDB
author: Valters IT
date: 2025-04-10
logsource:
    category: application
    product: golden_db
detection:
    selection:
        EventType: "Security"
        Action: "Privilege Escalation"
        User: "*"
        TargetUser: "admin|dba|root"
    condition: selection
falsepositives:
    - Legitimate administrative actions
level: high
tags:
    - attack.privilege_escalation
    - cve.2025.26706

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET 3306 (msg:"CVE-2025-26706 GoldenDB Privilege Escalation Attempt"; flow:to_server,established; content:"GRANT"; nocase; content:"TO"; distance:0; within:100; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Affected Systems: If possible, disconnect GoldenDB instances from untrusted networks.
2. Restrict Access: Use firewall rules to limit database access to only trusted IP addresses.
3. Review User Privileges: Audit all database accounts and remove unnecessary privileges.
4. Enable Auditing: Turn on detailed logging for all database operations, especially privilege changes.

Long-Term Fix:

• Vendor Patch: Monitor ZTE's official channels for a security patch. Apply it as soon as it becomes available.
• Upgrade: If a patched version is released, upgrade to it immediately.
• Workaround: If patching is not possible, consider implementing a database proxy or WAF that can inspect and block suspicious queries.

Compensating Controls:

• Implement multi-factor authentication (MFA) for database access.
• Use a database activity monitoring (DAM) solution to detect and alert on anomalous behavior.
• Conduct regular security assessments and penetration testing.

Valters IT
Securing Digital Frontiers