CVE-2019-25678: C4G Basic Laboratory Information SQLi

CVE-2019-25678 Overview

CVE-2019-25678 is a SQL injection vulnerability affecting C4G Basic Laboratory Information System (BLIS) version 3.4. The vulnerability allows unauthenticated attackers to execute arbitrary SQL commands by injecting malicious code through the site parameter. Attackers can send crafted GET requests to the users_select.php endpoint with SQL payloads to extract sensitive database information including patient records and system credentials.

Critical Impact

Unauthenticated remote attackers can extract sensitive healthcare data including patient records and system credentials through SQL injection, potentially leading to data breaches and unauthorized system access.

Affected Products

• C4G Basic Laboratory Information System 3.4

Discovery Timeline

• 2026-04-05 - CVE-2019-25678 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2019-25678

Vulnerability Analysis

This SQL injection vulnerability exists in the C4G Basic Laboratory Information System's user management functionality. The users_select.php endpoint fails to properly sanitize user-supplied input in the site parameter before incorporating it into SQL queries. This lack of input validation allows attackers to craft malicious requests that inject arbitrary SQL commands directly into the database backend.

The vulnerability is particularly concerning because it requires no authentication to exploit. An attacker with network access to the vulnerable application can craft HTTP GET requests containing SQL payloads and potentially extract the entire contents of the database, including sensitive patient health information, laboratory results, and system administrator credentials.

Healthcare applications like laboratory information systems typically store highly sensitive Protected Health Information (PHI), making this vulnerability especially critical from both a security and regulatory compliance perspective.

Root Cause

The root cause of CVE-2019-25678 is improper input validation and insufficient sanitization of the site parameter in the users_select.php endpoint. The application directly concatenates user input into SQL queries without using parameterized queries or prepared statements, creating a classic SQL injection attack surface. This falls under CWE-306 (Missing Authentication for Critical Function) as the vulnerable endpoint lacks proper authentication controls.

Attack Vector

The vulnerability is exploited via network-based attacks targeting the users_select.php endpoint. An attacker sends a specially crafted HTTP GET request with a malicious SQL payload in the site parameter. The vulnerable endpoint processes this input without sanitization and executes the injected SQL commands against the backend database.

The attack can be performed by any unauthenticated remote attacker who has network access to the C4G BLIS application. Successful exploitation enables attackers to read, modify, or delete database contents, potentially including patient medical records, user credentials, and system configuration data.

For detailed technical information about this vulnerability, see the VulnCheck Advisory and Exploit-DB entry #46438.

Detection Methods for CVE-2019-25678

Indicators of Compromise

• Unusual HTTP GET requests to users_select.php containing SQL keywords such as UNION, SELECT, INSERT, DROP, or -- comment sequences in the site parameter
• Database error messages or SQL syntax errors appearing in application logs
• Unexpected database queries or data access patterns from the BLIS application
• Evidence of data exfiltration or unauthorized database dumps

Detection Strategies

• Deploy web application firewall (WAF) rules to detect and block SQL injection patterns in HTTP requests to the BLIS application
• Enable and monitor database query logging for suspicious or malformed queries originating from the application
• Implement intrusion detection system (IDS) signatures for common SQL injection attack patterns targeting the users_select.php endpoint
• Review web server access logs for requests containing encoded SQL injection payloads or unusual parameter values

Monitoring Recommendations

• Configure alerting for repeated requests to users_select.php with unusual parameter values or SQL syntax
• Monitor database activity for bulk data extraction or unauthorized credential access
• Implement real-time log correlation to identify SQL injection attack patterns across multiple request attempts
• Establish baseline application behavior and alert on deviations in database query patterns

How to Mitigate CVE-2019-25678

Immediate Actions Required

• Restrict network access to the C4G BLIS application to trusted networks only until patching is complete
• Implement a web application firewall with SQL injection protection in front of the vulnerable application
• Review database access logs for evidence of prior exploitation and potential data exfiltration
• If the system has been compromised, rotate all database credentials and review patient data access logs

Patch Information

Organizations running C4G Basic Laboratory Information System version 3.4 should check with the vendor for available security updates. Review the VulnCheck Advisory for the latest remediation guidance and patch availability information.

Workarounds

• Deploy a web application firewall configured to block SQL injection attempts targeting the site parameter
• Implement network segmentation to limit access to the BLIS application from untrusted networks
• Add authentication requirements to the users_select.php endpoint if code modification is possible
• Consider taking the vulnerable endpoint offline if it is not critical to operations until a patch can be applied

# Example WAF rule to block SQL injection in site parameter
# ModSecurity rule example
SecRule ARGS:site "@detectSQLi" \
    "id:1001,\
    phase:2,\
    deny,\
    status:403,\
    log,\
    msg:'SQL Injection attempt detected in site parameter'"