CVE-2005-2538 in FlatNuke
Summary
by MITRE
FlatNuke 2.5.5 and possibly earlier versions allows remote attackers to obtain sensitive information via (1) a null byte or (2) an MS-DOS device name such as AUX, CON, PRN, COM1, or LPT1 in the mod parameter.
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Analysis
by VulDB Data Team • 07/10/2018
The vulnerability identified as CVE-2005-2538 affects FlatNuke version 2.5.5 and potentially earlier releases, representing a significant information disclosure weakness within the content management system. This flaw resides in the handling of user-supplied input parameters, specifically the mod parameter, which is processed without adequate validation or sanitization. The vulnerability stems from insufficient input filtering mechanisms that fail to properly handle special characters and reserved names commonly found in operating system file systems. Attackers can exploit this weakness by injecting null bytes or MS-DOS device names such as AUX, CON, PRN, COM1, or LPT1 into the mod parameter, which can lead to unintended system behavior and unauthorized data exposure.
The technical exploitation of this vulnerability occurs through the manipulation of the mod parameter within the FlatNuke application's request processing pipeline. When the application receives a request containing these special characters, the lack of proper input validation allows the system to interpret these values in unexpected ways. The null byte injection can potentially truncate strings or bypass certain security checks, while the MS-DOS device names can cause the application to attempt access to system resources that should remain protected. This type of vulnerability aligns with CWE-20, which describes improper input validation, and represents a classic case of insufficient sanitization of user-provided data. The attack vector operates entirely through HTTP requests, making it accessible to remote threat actors without requiring local system access or elevated privileges.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to gain insights into the underlying system structure and potentially access sensitive files or system resources. When attackers successfully exploit this weakness, they may be able to determine the existence of specific files, directories, or system components that should remain hidden from unauthorized users. The vulnerability's potential for escalation is significant since it can serve as a reconnaissance step for more sophisticated attacks, allowing adversaries to map the target environment and identify additional weaknesses. This information disclosure can be particularly damaging in environments where the FlatNuke application is deployed with sensitive data or where the system architecture contains information that could be leveraged for further exploitation.
Mitigation strategies for CVE-2005-2538 should focus on implementing robust input validation and sanitization mechanisms throughout the application's processing pipeline. The most effective approach involves filtering and rejecting any input containing null bytes or reserved MS-DOS device names before they can be processed by the application. Security measures should include the implementation of allowlists for valid parameter values, proper encoding of user input, and the deployment of web application firewalls that can detect and block malicious payloads containing these specific patterns. Organizations should also consider applying the latest available patches or upgrading to a more recent version of FlatNuke that addresses this vulnerability. From an operational security perspective, regular security assessments and code reviews should be conducted to identify similar input validation weaknesses that could potentially be exploited through various attack vectors. The remediation process should align with ATT&CK technique T1059.007 for command and script injection, ensuring that the application's input handling mechanisms prevent the execution of unintended system commands through malformed parameters.