CVE-2006-3136 in Nucleus
Summary
by MITRE
** DISPUTED ** Multiple PHP remote file inclusion vulnerabilities in Nucleus 3.23 allow remote attackers to execute arbitrary PHP code via a URL the DIR_LIBS parameter in (1) path/action.php, and to files in path/nucleus including (2) media.php, (3) /xmlrpc/server.php, and (4) /xmlrpc/api_metaweblog.inc.php. NOTE: this is a similar vulnerability to CVE-2006-2583. NOTE: this issue has been disputed by third parties, who state that the DIR_LIBS parameter is defined in an include file before being used.
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Analysis
by VulDB Data Team • 01/17/2025
The vulnerability described in CVE-2006-3136 represents a critical remote file inclusion flaw affecting Nucleus 3.23 content management system. This issue falls under the category of insecure direct object references and improper input validation, creating a pathway for malicious actors to execute arbitrary PHP code on vulnerable systems. The vulnerability specifically targets the DIR_LIBS parameter within multiple files including path/action.php, path/nucleus/media.php, path/xmlrpc/server.php, and path/xmlrpc/api_metaweblog.inc.php, demonstrating a widespread impact across the application's core functionality.
The technical exploitation of this vulnerability occurs through manipulation of the DIR_LIBS parameter, which is processed in a manner that allows attackers to inject malicious URLs into the include statement. This creates a remote code execution vector where attackers can load and execute arbitrary PHP scripts hosted on external servers. The flaw essentially allows attackers to bypass normal access controls and directly include files from remote locations, transforming what should be a local file inclusion mechanism into a dangerous remote code execution capability. This vulnerability aligns with CWE-88, which describes improper neutralization of special elements used in an OS command, and CWE-94, which covers execution of arbitrary code due to improper input handling in dynamic code generation.
The operational impact of this vulnerability is severe, as it provides attackers with complete control over the affected web server. Once exploited, attackers can execute malicious code with the privileges of the web server, potentially leading to data theft, system compromise, and further lateral movement within the network. The vulnerability's presence in multiple core files increases the attack surface significantly, making it more likely that an attacker can successfully exploit the system. The similarity to CVE-2006-2583 indicates this was part of a broader class of vulnerabilities affecting PHP applications that failed to properly validate and sanitize user input before using it in include statements. This type of vulnerability commonly maps to techniques described in the MITRE ATT&CK framework under T1059 for executing commands and T1566 for initial access through web applications.
The disputed nature of this vulnerability stems from the argument that the DIR_LIBS parameter is defined in an include file before being used, suggesting that the vulnerability may not exist in the manner described. However, this dispute does not diminish the potential security risk, as the fundamental issue remains the improper handling of user-supplied input in file inclusion operations. Organizations should treat this vulnerability with caution and implement proper input validation and sanitization measures regardless of the dispute status. The recommended mitigations include implementing strict input validation for all parameters used in include operations, using whitelisting approaches for file inclusion, and ensuring that user input cannot influence the inclusion of external files. Additionally, the application should be updated to a version that addresses this vulnerability, as the Nucleus CMS has likely released patches to resolve such issues. Security best practices dictate that all dynamic file inclusion should be carefully validated against a predefined set of allowed values, preventing attackers from injecting malicious URLs into the system.