CVE-2015-20121 in RealtyScripts
Summary
by MITRE • 03/16/2026
Next Click Ventures RealtyScript 4.0.2 contains SQL injection vulnerabilities that allow unauthenticated attackers to manipulate database queries by injecting arbitrary SQL code through the GET parameter 'u_id' in /admin/users.php and the POST parameter 'agent[]' in /admin/mailer.php. Attackers can exploit time-based blind SQL injection techniques to extract sensitive database information or cause denial of service through sleep-based payloads.
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Analysis
by VulDB Data Team • 03/20/2026
The vulnerability identified as CVE-2015-20121 affects Next Click Ventures RealtyScript version 4.0.2, a web application designed for real estate management and administration. This particular flaw represents a critical security weakness that exposes the application to unauthorized database manipulation by unauthenticated attackers. The vulnerability manifests through two distinct attack vectors within the administrative interface of the software, creating multiple pathways for exploitation that significantly increases the attack surface and potential impact of the security flaw.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the application's backend processing logic. Specifically, the GET parameter 'u_id' in the /admin/users.php file and the POST parameter 'agent[]' in /admin/mailer.php fail to properly sanitize user-supplied input before incorporating it into database query constructions. This lack of proper input filtering creates a condition where malicious actors can inject arbitrary SQL code directly into the application's database interaction layer. The vulnerability aligns with CWE-89, which categorizes SQL injection flaws as weaknesses that occur when an application fails to properly escape or validate user input before using it in SQL commands.
The operational impact of this vulnerability extends beyond simple data theft, as attackers can leverage time-based blind SQL injection techniques to systematically extract sensitive database information. Through carefully crafted payloads that introduce deliberate delays in database processing, threat actors can infer database contents and structure without direct output mechanisms. This approach allows for the extraction of user credentials, personal information, and potentially sensitive business data stored within the application's database. The vulnerability also enables denial of service conditions when attackers implement sleep-based payloads that cause the database server to pause execution, potentially leading to application unavailability and service disruption.
Security practitioners should consider this vulnerability in the context of the MITRE ATT&CK framework, specifically under the T1213 technique for Data from Information Repositories, and T1078 for Valid Accounts, as successful exploitation could provide attackers with persistent access to database resources and potentially escalate privileges within the application environment. The unauthenticated nature of this attack vector makes it particularly dangerous as it requires no prior authorization or credentials to exploit, significantly lowering the barrier to successful compromise. Organizations using this software should immediately implement input validation measures, including parameterized queries, proper escaping of special characters, and input length restrictions to prevent malicious SQL code injection.
Mitigation strategies should focus on immediate code-level fixes including the implementation of prepared statements and parameterized queries to prevent direct SQL injection. Additionally, input validation should be strengthened through the use of allowlists for acceptable characters and values, particularly for administrative parameters. Network-level protections such as web application firewalls can provide additional defense-in-depth measures, while regular security audits and penetration testing should be conducted to identify and remediate similar vulnerabilities. The vulnerability also highlights the importance of keeping web applications updated and patched, as this issue was likely resolved in subsequent versions of the RealtyScript software through proper input sanitization and validation mechanisms.