CVE-2005-2614 in Discuz
Summary
by MITRE
Discuz! 4.0 rc4 does not properly restrict types of files that are uploaded to the server, which allows remote attackers to execute arbitrary commands via a filename containing ".php.rar" or other multiple extensions that include .php.
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Analysis
by VulDB Data Team • 06/09/2019
The vulnerability identified as CVE-2005-2614 affects Discuz! version 4.0 rc4, a popular bulletin board system that was widely used for online forums and community platforms. This security flaw represents a critical file upload restriction bypass that enables remote attackers to execute arbitrary commands on the affected server. The vulnerability stems from inadequate validation of file extensions during the upload process, creating a pathway for malicious file execution that could compromise the entire web infrastructure.
The technical exploitation of this vulnerability relies on the server's failure to properly validate file types during upload operations. Attackers can craft malicious filenames containing multiple extensions such as ".php.rar" or other combinations that include ".php" as one of the extensions. When these files are uploaded to the server, the system processes them according to the last extension in the filename, effectively treating php files as archive files and allowing the php portion to execute. This behavior violates fundamental security principles of input validation and file type restriction, creating a dangerous attack vector that aligns with CWE-434, which specifically addresses the insecure upload of executable files.
The operational impact of this vulnerability is severe and multifaceted, as it allows attackers to gain unauthorized access to the server and execute arbitrary commands with the privileges of the web application. This could lead to complete system compromise, data theft, service disruption, and potential lateral movement within the network. The vulnerability affects not only the Discuz! application itself but also the underlying server infrastructure, as successful exploitation could result in persistent backdoor access, log manipulation, and unauthorized data exfiltration. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1190, which involves exploiting vulnerabilities in web applications to gain initial access and execute malicious code.
The security implications extend beyond immediate command execution to encompass broader system integrity threats. Once an attacker successfully uploads and executes malicious code through this vulnerability, they can establish persistent access, escalate privileges, and potentially use the compromised server as a launch point for attacks against other systems within the network. The vulnerability's impact is amplified by the fact that it affects a widely deployed forum software, meaning that many organizations could be simultaneously vulnerable. Organizations should implement immediate mitigations including proper file extension validation, content type checking, and the removal of file upload functionality for sensitive server operations. Additionally, regular security audits, proper input validation, and comprehensive patch management processes should be implemented to prevent similar vulnerabilities from occurring in future deployments.