CVE-2004-0529 in cPanel
Summary
by MITRE
The modified suexec program in cPanel, when configured for mod_php and compiled for Apache 1.3.31 and earlier without mod_phpsuexec, allows local users to execute untrusted shared scripts and gain privileges, as demonstrated using untainted scripts such as (1) proftpdvhosts or (2) addalink.cgi, a different vulnerability than CVE-2004-0490.
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Analysis
by VulDB Data Team • 07/07/2017
The vulnerability described in CVE-2004-0529 represents a critical privilege escalation flaw within the cPanel suexec implementation that specifically affects Apache 1.3.31 and earlier versions. This issue arises from the improper handling of shared hosting environments where multiple users operate under the same web server infrastructure. The modified suexec program, when configured to work with mod_php and compiled without mod_phpsuexec, creates an exploitable condition that allows local users to bypass security restrictions and execute arbitrary code with elevated privileges. The vulnerability specifically targets the execution context where user scripts are processed, enabling attackers to manipulate the execution environment through carefully crafted shared scripts.
The technical flaw manifests in the improper execution flow of the suexec mechanism, which is designed to allow users to execute CGI scripts with the privileges of the script owner rather than the web server user. When cPanel's modified suexec operates in conjunction with mod_php without the proper mod_phpsuexec configuration, it fails to properly validate or sanitize the execution context of shared scripts. This creates a scenario where untrusted scripts can be executed in an environment that grants elevated privileges, effectively allowing local users to gain root or administrative access to the hosting environment. The vulnerability demonstrates a classic case of insufficient input validation and privilege management, where the system fails to properly isolate user execution contexts.
The operational impact of this vulnerability is severe for shared hosting environments that rely on cPanel for management and Apache 1.3.31 or earlier versions for web serving. Attackers can exploit this weakness by leveraging untainted scripts such as proftpdvhosts or addalink.cgi, which are typically used for legitimate system administration tasks but can be manipulated to execute malicious code. This vulnerability enables attackers to escalate privileges from regular user accounts to system-level access, potentially compromising entire hosting environments and affecting multiple users. The attack vector is particularly dangerous because it operates within the legitimate execution paths of the system, making detection more challenging. According to CWE standards, this vulnerability maps to CWE-269: "Improper Privilege Management" and CWE-78: "Improper Neutralization of Special Elements used in OS Command Injection," reflecting the privilege escalation and command injection aspects of the flaw.
The exploitation of CVE-2004-0529 aligns with several techniques documented in the MITRE ATT&CK framework, particularly in the privilege escalation and execution domains. The attack follows the pattern of leveraging system misconfigurations to gain elevated privileges, which corresponds to ATT&CK technique T1068: "Exploitation for Privilege Escalation." The use of shared scripts as attack vectors demonstrates the T1059.001: "Command and Scripting Interpreter: PowerShell" and T1059.007: "Command and Scripting Interpreter: JavaScript" techniques, where attackers manipulate legitimate execution paths to achieve their objectives. Organizations using affected cPanel configurations face significant risk of unauthorized access, data compromise, and potential full system takeover.
Mitigation strategies for this vulnerability require immediate attention to cPanel configuration and Apache version management. System administrators should upgrade to Apache 1.3.32 or later versions where the suexec behavior has been corrected, or ensure that mod_phpsuexec is properly configured to prevent the privilege escalation scenario. The recommended approach involves disabling mod_php in the affected configuration or implementing proper privilege separation mechanisms that prevent untrusted scripts from executing with elevated privileges. Additionally, organizations should implement strict input validation, regular security audits of shared hosting environments, and monitoring for unusual execution patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper privilege management in shared hosting environments and underscores the need for comprehensive security configurations that prevent unauthorized privilege escalation through legitimate system components.