CVE-2005-0239 in SMIME Plugin
Summary
by MITRE
viewcert.php in the S/MIME plugin 0.4 and 0.5 for Squirrelmail allows remote attackers to execute arbitrary commands via shell metacharacters in the cert parameter.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability identified as CVE-2005-0239 represents a critical command injection flaw within the S/MIME plugin version 0.4 and 0.5 for Squirrelmail email client software. This vulnerability specifically affects the viewcert.php script which processes certificate information within the S/MIME plugin functionality. The flaw arises from insufficient input validation and sanitization of user-provided data, particularly in the cert parameter that is processed without proper escaping or filtering of shell metacharacters. This allows malicious actors to inject and execute arbitrary system commands on the affected server, potentially leading to complete system compromise and unauthorized access to sensitive email communications and user data.
The technical implementation of this vulnerability stems from improper handling of user input within the S/MIME plugin's certificate viewing functionality. When the viewcert.php script processes the cert parameter, it fails to sanitize or escape special shell characters such as semicolons, ampersands, backticks, and pipes that could be used to chain commands. This vulnerability directly maps to CWE-77 which categorizes improper neutralization of special elements used in a command, and more specifically to CWE-94 which addresses the execution of arbitrary code or commands. The vulnerability exists due to a lack of proper input validation and output encoding practices, which are fundamental security controls recommended by the OWASP Top Ten and the SANS Institute's Top 25 Software Errors.
The operational impact of this vulnerability is severe and multifaceted, as it provides remote attackers with the capability to execute arbitrary commands on the target system with the privileges of the web server process. An attacker could potentially escalate privileges, access sensitive email data, compromise user accounts, or establish persistent backdoors within the email infrastructure. The vulnerability affects organizations using Squirrelmail with the affected S/MIME plugin versions, making it particularly dangerous in enterprise environments where email systems serve as critical communication channels. The attack vector is straightforward, requiring only a web browser to craft malicious payloads that exploit the command injection vulnerability, making it accessible to attackers with minimal technical expertise and potentially leading to widespread compromise of email systems.
Mitigation strategies for CVE-2005-0239 should focus on immediate patching and remediation actions to address the root cause of the vulnerability. The primary solution involves upgrading to a patched version of the S/MIME plugin that properly sanitizes user input and implements proper command execution controls. Organizations should also implement input validation mechanisms that filter or escape special shell characters before processing user data, and consider implementing web application firewalls to detect and block suspicious command injection attempts. Additional defensive measures include restricting web server privileges to minimize potential damage from successful exploitation, implementing proper access controls for the S/MIME plugin functionality, and conducting regular security assessments of email systems to identify similar vulnerabilities. This vulnerability also highlights the importance of following secure coding practices and input validation as outlined in the MITRE ATT&CK framework's command and scripting interpreter tactics, where adversaries often exploit such injection vulnerabilities to gain unauthorized access and execute malicious code within target environments.