CVE-2004-1956 in PostNuke
Summary
by MITRE
PostNuke 0.7.2.6 allows remote attackers to gain information via a direct HTTP request to files in the (1) includes/blocks directory, (2) pnadodb directory, (3) NS-NewUser module, (4) NS-Your_Account, (5) NS-LostPassword module, or (6) NS-User module which reveals the path to the web server in a PHP error message.
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Analysis
by VulDB Data Team • 06/08/2019
This vulnerability in PostNuke 0.7.2.6 represents a critical information disclosure flaw that exposes sensitive system details through improperly handled HTTP requests. The vulnerability occurs when remote attackers can directly access specific files within well-defined directories including includes/blocks, pnadodb, and several NS modules such as NS-NewUser, NS-Your_Account, NS-LostPassword, and NS-User. When these files are accessed directly, they generate PHP error messages that inadvertently reveal the absolute path to the web server installation directory. This type of information disclosure vulnerability falls under CWE-200, which specifically addresses the exposure of sensitive information through error messages and diagnostic output. The flaw demonstrates a fundamental lack of proper input validation and error handling within the application's file access mechanisms, creating a pathway for attackers to gather reconnaissance information that could be leveraged for more sophisticated attacks.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with crucial system architecture details that can inform subsequent exploitation attempts. The revealed server paths can help attackers understand the directory structure, potentially exposing weaknesses in the application's security model and enabling them to craft more targeted attacks against other components. This vulnerability directly maps to techniques described in the ATT&CK framework under T1212, which covers exploitation for credential access through the discovery of system information. The exposure of file paths can also aid in identifying potential privilege escalation vectors, as attackers may discover that certain files are accessible with elevated permissions or contain sensitive configuration data that would otherwise remain hidden.
The technical implementation of this vulnerability stems from the application's failure to properly validate and sanitize file access requests within the specified directories. When PHP scripts in these locations encounter errors or are accessed inappropriately, they generate error messages containing the full server path rather than handling the error gracefully or redirecting appropriately. This occurs because the application lacks proper error handling mechanisms and access control checks for these specific file paths. The vulnerability is particularly concerning because it affects multiple core directories that are essential to the application's functionality, indicating a systemic issue in the application's security architecture rather than an isolated flaw. Security researchers and penetration testers can exploit this by simply making direct HTTP requests to the affected paths and observing the error messages that contain the server path information. This makes the vulnerability easily exploitable and difficult to detect through routine security scanning, as it occurs in legitimate application paths rather than unusual or suspicious locations.
Mitigation strategies for this vulnerability should focus on implementing comprehensive error handling and access control measures throughout the affected directories. The primary remediation involves modifying the application code to prevent direct access to sensitive files in the includes/blocks, pnadodb, and NS modules directories, while also implementing proper error handling that does not expose server path information. Organizations should also consider implementing web application firewalls that can detect and block direct access attempts to these specific paths, as well as establishing proper logging mechanisms to monitor for such access attempts. The solution should align with security best practices outlined in OWASP Top Ten and NIST cybersecurity frameworks, particularly focusing on input validation, proper error handling, and access control. Additionally, regular security audits should be conducted to ensure that similar vulnerabilities do not exist in other parts of the application, as this flaw represents a pattern of insufficient security controls that may be present in other areas of the codebase.