CVE-2005-4724 in PhpTagCool
Summary
by MITRE
SQL injection vulnerability in post.php in PhpTagCool 1.0.3 allows remote attackers to execute arbitrary SQL commands via the X-Forwarded-For field in an HTTP header.
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Analysis
by VulDB Data Team • 10/23/2025
The vulnerability identified as CVE-2005-4724 represents a critical SQL injection flaw within the PhpTagCool 1.0.3 web application, specifically affecting the post.php script. This vulnerability arises from insufficient input validation and sanitization of user-supplied data within HTTP headers, particularly the X-Forwarded-For field that is commonly used to identify the original IP address of a client connecting to a web server through an HTTP proxy or load balancer. The flaw enables remote attackers to inject malicious SQL commands into the application's database queries, potentially compromising the entire backend database system.
The technical implementation of this vulnerability stems from the application's failure to properly escape or validate the X-Forwarded-For HTTP header value before incorporating it into SQL database queries. When a malicious actor sends a specially crafted HTTP request containing crafted SQL payloads within the X-Forwarded-For header field, the application processes this unvalidated input directly into database operations without proper sanitization. This design flaw falls under the Common Weakness Enumeration category CWE-89, which specifically addresses SQL injection vulnerabilities where untrusted data is directly included in SQL commands without proper escaping or parameterization. The vulnerability is particularly concerning because it operates at the HTTP header level rather than through conventional form inputs, making it more difficult to detect and prevent using standard web application firewall rules.
The operational impact of this vulnerability extends beyond simple data theft, as it provides attackers with the capability to execute arbitrary SQL commands on the affected database server. This could enable unauthorized access to sensitive information, data modification or deletion, privilege escalation, and potentially full system compromise. Attackers could leverage this vulnerability to extract confidential user data, modify database records, create new user accounts with administrative privileges, or even execute operating system commands if the database server allows such functionality. The remote nature of the attack means that exploitation can occur from anywhere on the internet without requiring physical access to the target network, making it particularly dangerous for web applications hosting sensitive data. This vulnerability aligns with the attack pattern described in the MITRE ATT&CK framework under the technique T1071.004 for Application Layer Protocol: DNS, where attackers exploit web application vulnerabilities to gain unauthorized access to backend systems.
Mitigation strategies for CVE-2005-4724 require immediate implementation of proper input validation and sanitization measures throughout the application's codebase. The primary defense involves implementing parameterized queries or prepared statements for all database operations, ensuring that user-supplied data cannot be interpreted as SQL commands regardless of its content. Additionally, the application should validate and sanitize all HTTP header inputs, including the X-Forwarded-For field, by implementing strict input filtering that removes or escapes potentially dangerous characters such as single quotes, semicolons, and SQL keywords. Network-level protections should include implementing web application firewalls that can detect and block suspicious header patterns, while application-level protections require comprehensive code reviews to identify and remediate similar vulnerabilities in other input handling functions. Organizations should also implement proper access controls and database permissions to limit the damage that could result from successful exploitation, ensuring that database accounts used by web applications have minimal necessary privileges to reduce the potential impact of SQL injection attacks. The vulnerability demonstrates the importance of following secure coding practices and adhering to the principle of least privilege in database access design.