CVE-2025-6918: Ncvav Virtual PBX Software SQLi Flaw

CVE-2025-6918 Overview

CVE-2025-6918 is a critical SQL Injection vulnerability affecting Ncvav Virtual PBX Software. The vulnerability exists due to improper neutralization of special elements used in SQL commands, allowing attackers to inject malicious SQL statements and potentially compromise the entire database backend of affected PBX systems.

Critical Impact

This SQL Injection vulnerability enables unauthenticated remote attackers to execute arbitrary SQL commands, potentially leading to complete database compromise, data exfiltration, and unauthorized system access.

Affected Products

• Ncvav Virtual PBX Software versions before 09.07.2025

Discovery Timeline

• 2025-07-28 - CVE-2025-6918 published to NVD
• 2025-07-29 - Last updated in NVD database

Technical Details for CVE-2025-6918

Vulnerability Analysis

This vulnerability falls under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command). The Virtual PBX Software fails to properly sanitize user-supplied input before incorporating it into SQL queries. This allows an attacker to manipulate the structure of SQL statements by injecting specially crafted input containing SQL metacharacters and commands.

The network-accessible nature of this vulnerability combined with no authentication requirements creates a significant attack surface. Successful exploitation could result in unauthorized access to sensitive call records, voicemail data, user credentials, and PBX configuration settings stored in the backend database.

Root Cause

The root cause of this vulnerability stems from insufficient input validation and the lack of parameterized queries or prepared statements in the Ncvav Virtual PBX Software. User-controlled data is directly concatenated into SQL query strings without proper escaping or sanitization of SQL special characters such as single quotes, double quotes, semicolons, and comment markers.

Attack Vector

The vulnerability is exploitable over the network without requiring authentication or user interaction. An attacker can craft malicious HTTP requests containing SQL injection payloads targeting vulnerable parameters in the PBX web interface. Common attack techniques include:

• Union-based SQL injection to extract data from other tables
• Boolean-based blind injection to infer database contents
• Time-based blind injection using database delay functions
• Stacked queries to execute multiple SQL statements including INSERT, UPDATE, or DELETE operations

The attack can be conducted remotely against any exposed Ncvav Virtual PBX Software instance accessible over the network. For detailed technical information, refer to the USOM Security Notification TR-25-0180.

Detection Methods for CVE-2025-6918

Indicators of Compromise

• Unusual database queries containing SQL metacharacters (single quotes, double dashes, UNION SELECT statements) in web server logs
• Unexpected database errors or timeout responses from the PBX application
• Evidence of data exfiltration or unauthorized data access in database audit logs
• Anomalous outbound network connections from the database server

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block common SQL injection patterns
• Monitor web server access logs for requests containing SQL injection signatures such as ' OR 1=1, UNION SELECT, or ; DROP TABLE
• Implement database activity monitoring to detect unusual query patterns or unauthorized data access
• Configure intrusion detection systems (IDS) with signatures for SQL injection attack vectors

Monitoring Recommendations

• Enable detailed logging on the Ncvav Virtual PBX application and associated database servers
• Establish baseline metrics for normal database query patterns and alert on deviations
• Monitor for failed authentication attempts and abnormal session behavior that may indicate exploitation attempts
• Review network traffic logs for suspicious payloads targeting PBX management interfaces

How to Mitigate CVE-2025-6918

Immediate Actions Required

• Update Ncvav Virtual PBX Software to version 09.07.2025 or later immediately
• Restrict network access to the PBX management interface using firewall rules to limit exposure
• Implement Web Application Firewall (WAF) rules to block SQL injection attempts as a temporary measure
• Audit database logs for evidence of prior exploitation attempts

Patch Information

Ncvav has addressed this vulnerability in Virtual PBX Software version 09.07.2025 and later releases. Organizations should obtain the patched version from their Ncvav vendor or support channel. For additional guidance, consult the USOM Security Notification TR-25-0180.

Workarounds

• Implement strict network segmentation to isolate PBX systems from untrusted networks
• Deploy a reverse proxy with SQL injection filtering capabilities in front of the PBX web interface
• Disable or restrict access to non-essential PBX management features until patching is complete
• Implement database-level access controls to minimize the impact of potential SQL injection attacks

# Example: Restrict network access to PBX management interface using iptables
# Allow access only from trusted management network
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP