CVE-2015-20120: RealtyScript SQL Injection Vulnerability

CVE-2015-20120 Overview

Next Click Ventures RealtyScript 4.0.2 contains multiple time-based blind SQL injection vulnerabilities that allow unauthenticated attackers to extract database information by injecting SQL code into application parameters. Attackers can craft requests with time-delay payloads to infer database contents character by character based on response timing differences.

Critical Impact

Unauthenticated attackers can extract sensitive database contents including user credentials, property listings, and other confidential information through SQL injection attacks without any authentication requirements.

Affected Products

• Next Click Ventures RealtyScript version 4.0.2

Discovery Timeline

• 2026-03-16 - CVE CVE-2015-20120 published to NVD
• 2026-03-19 - Last updated in NVD database

Technical Details for CVE-2015-20120

Vulnerability Analysis

This vulnerability is classified as SQL Injection (CWE-89), specifically a time-based blind SQL injection. The RealtyScript application fails to properly sanitize user-supplied input before incorporating it into SQL queries. This lack of input validation allows attackers to inject malicious SQL code that gets executed by the database server.

Time-based blind SQL injection is particularly insidious because it does not rely on visible error messages or data being returned in the response. Instead, attackers leverage database-specific time delay functions (such as SLEEP() in MySQL or WAITFOR DELAY in MSSQL) to infer information about the database structure and contents based on how long the server takes to respond.

Root Cause

The root cause of this vulnerability lies in improper input validation and the direct concatenation of user-supplied data into SQL queries without adequate sanitization or the use of parameterized queries. Multiple application parameters are vulnerable, indicating a systemic failure in secure coding practices throughout the application's data handling routines.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can remotely send specially crafted HTTP requests containing time-delay SQL injection payloads to vulnerable application parameters. By measuring response times, the attacker can systematically extract database information one character at a time.

The exploitation process typically involves:

1. Identifying vulnerable input parameters through initial probing with simple time-delay payloads
2. Confirming the injection point by observing measurable delays in server responses
3. Using conditional SQL statements combined with time delays to extract data character by character
4. Automating the extraction process with tools like SQLMap to retrieve complete database contents

For detailed technical information and proof-of-concept examples, refer to the Exploit-DB #38497 entry and the Zero Science Vulnerability ZSL-2015-5270 advisory.

Detection Methods for CVE-2015-20120

Indicators of Compromise

• HTTP requests containing SQL time-delay functions such as SLEEP(), WAITFOR DELAY, BENCHMARK(), or pg_sleep() in parameters
• Unusually long response times from the web application that correlate with specific request patterns
• Database query logs showing repeated similar queries with time-delay functions
• Automated scanning tool signatures in web server logs (e.g., SQLMap user agents or request patterns)

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block SQL injection patterns, including time-based payloads
• Configure database query logging and monitor for suspicious queries containing time-delay functions
• Deploy network intrusion detection systems (IDS) with SQL injection detection signatures
• Analyze web server access logs for patterns indicative of automated SQL injection scanning

Monitoring Recommendations

• Monitor database server CPU and response time metrics for anomalies that may indicate ongoing time-based SQL injection attacks
• Set up alerts for requests with unusually long server processing times
• Regularly audit application logs for SQL error messages or unusual query patterns
• Implement real-time security monitoring on web application endpoints handling user input

How to Mitigate CVE-2015-20120

Immediate Actions Required

• Immediately take the affected RealtyScript 4.0.2 application offline or restrict access until patched
• Deploy a Web Application Firewall (WAF) with SQL injection protection rules in front of the application
• Conduct a security audit of all user input handling in the application
• Review database access controls and ensure the application uses least-privilege database accounts

Patch Information

Consult the VulnCheck Advisory for the latest remediation guidance. Contact Next Click Ventures directly for information about security patches or updated versions of RealtyScript that address these SQL injection vulnerabilities.

Workarounds

• Implement strict input validation and sanitization on all user-supplied parameters
• Deploy parameterized queries or prepared statements throughout the application codebase
• Configure a WAF to block requests containing SQL injection payloads
• Restrict database user permissions to minimum required privileges to limit the impact of successful exploitation
• Consider placing the application behind a reverse proxy with additional security controls

# Example WAF rule configuration for SQL injection protection
# ModSecurity example rule to block time-based SQL injection patterns
SecRule ARGS "@rx (?i)(sleep\s*\(|benchmark\s*\(|waitfor\s+delay|pg_sleep)" \
    "id:1001,phase:2,deny,status:403,msg:'SQL Injection - Time-based payload detected'"