CVE-2021-47766: Kmaleon Authenticated SQL Injection Flaw

CVE-2021-47766 Overview

CVE-2021-47766 is an authenticated SQL injection vulnerability affecting Kmaleon version 1.1.0.205. The vulnerability exists in the tipocomb parameter of the kmaleonW.php script, allowing authenticated attackers to manipulate database queries. Attackers can exploit this flaw using boolean-based, error-based, and time-based blind SQL injection techniques to potentially extract sensitive information or manipulate database contents.

Critical Impact

Authenticated attackers can exploit this SQL injection vulnerability to extract sensitive database information, modify data integrity, or potentially escalate their access within the application through database manipulation.

Affected Products

• Kmaleon 1.1.0.205

Discovery Timeline

• 2026-01-15 - CVE CVE-2021-47766 published to NVD
• 2026-01-16 - Last updated in NVD database

Technical Details for CVE-2021-47766

Vulnerability Analysis

This SQL injection vulnerability (CWE-89: Improper Neutralization of Special Elements used in an SQL Command) occurs due to insufficient input validation and sanitization in the kmaleonW.php script. The tipocomb parameter accepts user-supplied input that is directly incorporated into SQL queries without proper parameterization or escaping.

The vulnerability requires authentication, meaning an attacker must first possess valid credentials to access the vulnerable endpoint. However, once authenticated, the attacker can leverage the SQL injection to interact directly with the underlying database. The vulnerability is accessible over the network, requires low complexity to exploit, and can lead to high confidentiality impact with some integrity impact on the affected system.

Root Cause

The root cause of CVE-2021-47766 is the failure to properly sanitize user-supplied input in the tipocomb parameter before incorporating it into database queries. Instead of using parameterized queries or prepared statements, the application appears to construct SQL statements through string concatenation, allowing attackers to inject malicious SQL syntax.

Attack Vector

The attack vector for this vulnerability is network-based, requiring authenticated access to the application. An attacker with valid credentials can send specially crafted requests to the kmaleonW.php endpoint with malicious SQL payloads in the tipocomb parameter. The vulnerability supports multiple exploitation techniques:

• Boolean-based blind SQL injection: Attackers can infer database contents by observing different application responses based on true/false SQL conditions
• Error-based SQL injection: Database error messages may be leveraged to extract information about the database structure and contents
• Time-based blind SQL injection: Attackers can use SQL delay functions to confirm injection success and extract data based on response timing

Technical details and proof-of-concept information are available in the Exploit-DB #50499 advisory.

Detection Methods for CVE-2021-47766

Indicators of Compromise

• Unusual or malformed requests to kmaleonW.php containing SQL syntax in the tipocomb parameter
• Web server logs showing requests with SQL keywords such as UNION, SELECT, SLEEP, WAITFOR, or BENCHMARK in URL parameters
• Database error messages appearing in application responses or logs
• Unexpected database query patterns or elevated query execution times

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block SQL injection patterns targeting the tipocomb parameter
• Deploy intrusion detection/prevention systems with signatures for common SQL injection payloads
• Enable detailed logging on web servers and database servers to capture suspicious query patterns
• Use database activity monitoring tools to identify anomalous SQL statements

Monitoring Recommendations

• Monitor access logs for kmaleonW.php requests with unusual parameter values
• Set up alerts for database errors or exceptions originating from the Kmaleon application
• Implement query performance monitoring to detect time-based injection attempts
• Review authentication logs for accounts repeatedly accessing the vulnerable endpoint

How to Mitigate CVE-2021-47766

Immediate Actions Required

• Restrict network access to the Kmaleon application to trusted IP addresses only
• Implement additional authentication controls or multi-factor authentication
• Deploy a web application firewall with SQL injection protection rules
• Review and audit user accounts with access to the application

Patch Information

No official vendor patch information is currently available for CVE-2021-47766. Organizations should monitor vendor communications for security updates. Additional product information may be available through the Web Archive Kmaleon Abogados page.

Workarounds

• Implement input validation at the network perimeter using a WAF to filter SQL injection patterns
• Restrict access to the kmaleonW.php endpoint to only necessary users and IP ranges
• Consider disabling or removing the vulnerable functionality if not business-critical
• Apply application-level input filtering to sanitize the tipocomb parameter if source code access is available

Organizations should prioritize upgrading or migrating away from vulnerable versions of Kmaleon, implementing compensating controls until a patch is available from the vendor.