CVE-2018-25194: Nominas 0.27 SQL Injection Vulnerability

CVE-2018-25194 Overview

Nominas 0.27 contains an SQL injection vulnerability that allows unauthenticated attackers to execute arbitrary SQL queries by injecting malicious code through the username parameter. Attackers can send POST requests to the login/checklogin.php endpoint with crafted UNION-based SQL injection payloads to extract database information including usernames, database names, and version details.

Critical Impact

Unauthenticated attackers can extract sensitive database information and potentially compromise the entire application database through SQL injection attacks targeting the authentication mechanism.

Affected Products

• Nominas version 0.27

Discovery Timeline

• 2026-03-06 - CVE CVE-2018-25194 published to NVD
• 2026-03-09 - Last updated in NVD database

Technical Details for CVE-2018-25194

Vulnerability Analysis

This SQL injection vulnerability exists in the authentication mechanism of Nominas 0.27. The application fails to properly sanitize user-supplied input in the username parameter before incorporating it into SQL queries. This classic input validation flaw allows attackers to manipulate the query logic by injecting malicious SQL statements.

The vulnerability is particularly dangerous because it affects the login endpoint (login/checklogin.php), which is publicly accessible without authentication. This means any remote attacker can exploit this flaw without needing any credentials or prior access to the system.

Root Cause

The root cause of this vulnerability is improper input validation and the use of unsanitized user input directly within SQL queries. The checklogin.php script does not implement parameterized queries or prepared statements, allowing special SQL characters and commands to be interpreted as part of the database query rather than as literal string values.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker sends specially crafted POST requests to the login/checklogin.php endpoint with UNION-based SQL injection payloads in the username field. These payloads allow the attacker to:

1. Bypass authentication controls
2. Extract database schema information
3. Retrieve sensitive data such as usernames and passwords
4. Enumerate database version and configuration details

The vulnerability can be exploited using standard SQL injection techniques. Attackers craft UNION SELECT statements to append additional queries that extract data from other tables or database metadata. Technical details and proof-of-concept information are available through the Exploit-DB #45820 advisory and the VulnCheck SQL Injection Advisory.

Detection Methods for CVE-2018-25194

Indicators of Compromise

• Unusual POST requests to login/checklogin.php containing SQL keywords such as UNION, SELECT, FROM, or --
• Web server logs showing repeated authentication attempts with special characters in username fields
• Database logs indicating unexpected queries or access to system tables like information_schema
• Error messages in application logs revealing SQL syntax errors or database structure information

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block SQL injection patterns in POST parameters
• Configure intrusion detection systems (IDS) to alert on requests containing common SQL injection payloads
• Enable detailed logging on database servers to capture and analyze query patterns
• Deploy SentinelOne Singularity to detect exploitation attempts and anomalous application behavior

Monitoring Recommendations

• Monitor web server access logs for requests to login/checklogin.php with unusually long or encoded parameter values
• Set up alerts for database queries that access sensitive system tables or contain UNION statements
• Review authentication failure patterns that may indicate probing or exploitation attempts
• Implement real-time log correlation to identify SQL injection attack chains

How to Mitigate CVE-2018-25194

Immediate Actions Required

• Restrict access to the Nominas application from untrusted networks until patches can be applied
• Deploy Web Application Firewall rules to filter SQL injection attempts targeting the login endpoint
• Implement network segmentation to limit database access from compromised web servers
• Review database user permissions and apply principle of least privilege

Patch Information

No official vendor patch information is currently available. Organizations should consult the VulnCheck SQL Injection Advisory for the latest remediation guidance. Consider upgrading to a newer version of Nominas if available, or implementing compensating controls.

Workarounds

• Deploy a reverse proxy or WAF in front of the application to filter malicious input containing SQL injection patterns
• Modify the checklogin.php script to use prepared statements or parameterized queries if source code access is available
• Implement input validation at the application layer to reject username values containing SQL metacharacters
• Consider disabling the vulnerable login endpoint and implementing alternative authentication mechanisms

# Example WAF rule to block SQL injection attempts (ModSecurity)
SecRule ARGS:username "@rx (?i)(union|select|insert|update|delete|drop|--)" \
    "id:1001,phase:2,deny,status:403,msg:'SQL Injection Attempt Blocked'"