CVE-2001-0436 in DCForum
Summary
by MITRE
dcboard.cgi in DCForum 2000 1.0 allows remote attackers to execute arbitrary commands by uploading a Perl program to the server and using a .. (dot dot) in the AZ parameter to reference the program.
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Analysis
by VulDB Data Team • 05/22/2019
The vulnerability described in CVE-2001-0436 represents a critical directory traversal flaw in DCForum 2000 version 1.0's dcboard.cgi script. This vulnerability stems from improper input validation and path manipulation handling within the application's file processing functionality. The flaw specifically manifests when the application accepts user-supplied input through the AZ parameter without adequate sanitization or validation, creating an opportunity for attackers to manipulate file paths and execute arbitrary code on the target system.
The technical exploitation mechanism involves uploading a malicious Perl script to the server's file system through the vulnerable upload functionality, followed by crafting a specially formatted request that includes directory traversal sequences using the .. (dot dot) notation in the AZ parameter. This allows attackers to reference and execute the uploaded Perl program from locations outside the intended directory structure, effectively bypassing access controls and executing arbitrary commands with the privileges of the web server process. The vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as directory traversal or path traversal attacks.
The operational impact of this vulnerability is severe and multifaceted, as it provides remote attackers with complete system compromise capabilities. Successful exploitation enables attackers to execute arbitrary commands, potentially leading to full system takeover, data exfiltration, and persistent backdoor installation. The vulnerability affects the confidentiality, integrity, and availability of the affected system, as attackers can modify or delete critical system files, install malware, and maintain unauthorized access. This type of vulnerability falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter, specifically Perl, and T1566.001 for Phishing, as attackers often use such vulnerabilities to deliver malicious payloads through compromised web applications.
Mitigation strategies for this vulnerability should focus on immediate patching of the affected DCForum version, as no reliable workarounds exist for this specific flaw. Organizations should implement proper input validation and sanitization measures to prevent directory traversal attacks, including strict validation of all user-supplied input parameters. The application should enforce proper access controls and file path restrictions, ensuring that all file operations occur within designated directories. Additionally, implementing web application firewalls, input filtering mechanisms, and regular security audits can help prevent similar vulnerabilities from being exploited. The vulnerability also highlights the importance of secure coding practices and proper validation of file operations, as outlined in OWASP Top 10 2017 category A04:2017 - Injection and the principle of least privilege enforcement in web application security.