CVE-2006-1200 in Link Bank
Summary
by MITRE
Direct static code injection vulnerability in add_link.txt in daverave Link Bank allows remote attackers to execute arbitrary PHP code via the url_name parameter, which is not sanitized before being stored in links.txt, which is later used in an include statement.
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Analysis
by VulDB Data Team • 08/06/2017
This vulnerability exists in the daverave Link Bank application where a direct static code injection flaw is present in the add_link.txt component. The vulnerability stems from inadequate input validation and sanitization of user-supplied data in the url_name parameter. When an attacker submits malicious code through this parameter, the application fails to properly sanitize the input before storing it in the links.txt file. This stored data is subsequently included in the application's execution flow through an include statement, creating a classic code injection vector that allows remote attackers to execute arbitrary PHP code on the target system. The flaw represents a critical security weakness that directly enables remote code execution and can be exploited without authentication, making it particularly dangerous in web applications where user input is processed and stored.
The technical implementation of this vulnerability follows a well-documented pattern of insecure direct object reference combined with code injection. The url_name parameter is directly incorporated into the application's file handling logic without proper sanitization or validation, creating a pathway for attackers to inject malicious PHP code that gets executed during subsequent include operations. This vulnerability is classified as a direct static code injection, which aligns with CWE-94, specifically CWE-94: "Improper Control of Generation of Code ('Code Injection')" and also relates to CWE-20: "Improper Input Validation." The vulnerability operates at the application layer where user input is processed and becomes part of executable code, making it a prime target for attackers seeking to escalate privileges or compromise the entire web server.
The operational impact of this vulnerability is severe and multifaceted. Remote attackers can execute arbitrary PHP code with the privileges of the web server process, potentially leading to complete system compromise, data exfiltration, and further lateral movement within the network. The vulnerability allows for persistent code execution since the malicious input is stored in the links.txt file and remains active until manually removed. This type of vulnerability can be exploited to establish backdoors, install malware, modify or delete critical application data, and access sensitive information stored on the server. The attack vector is particularly dangerous because it requires no authentication and can be exploited through simple HTTP requests, making it highly accessible to attackers with basic web exploitation skills.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements. The primary fix involves implementing strict input validation and sanitization for all user-supplied data, particularly parameters that are later used in include or eval operations. Applications should employ proper escaping mechanisms for special characters and implement whitelisting approaches for acceptable input formats. Additionally, the application should avoid using user-supplied data directly in include statements and instead use secure lookup mechanisms or prepared statements. Organizations should also implement proper access controls and file permissions to limit the impact of potential exploitation. This vulnerability highlights the importance of following secure coding practices and adheres to ATT&CK technique T1059.007: "Command and Scripting Interpreter: PHP" which emphasizes the need for proper input validation and code execution safeguards in web applications. Regular security audits and input validation testing should be implemented to prevent similar vulnerabilities from being introduced in future development cycles.