CVE-2008-6544 in Simple Machines
Summary
by MITRE
** DISPUTED ** Multiple PHP remote file inclusion vulnerabilities in Simple Machines Forum (SMF) 1.1.4 allow remote attackers to execute arbitrary PHP code via a URL in the (1) settings[default_theme_dir] parameter to Sources/Subs-Graphics.php and (2) settings[default_theme_dir] parameter to Sources/Themes.php. NOTE: CVE and multiple third parties dispute this issue because the files contain a protection mechanism against direct request.
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Analysis
by VulDB Data Team • 10/16/2025
The vulnerability identified as CVE-2008-6544 pertains to multiple remote file inclusion flaws discovered in Simple Machines Forum version 1.1.4, a widely used bulletin board system. This issue represents a critical security weakness that could potentially allow malicious actors to execute arbitrary PHP code on affected systems. The vulnerability manifests through two distinct attack vectors targeting the settings[default_theme_dir] parameter within the Sources/Subs-Graphics.php and Sources/Themes.php files, making it particularly concerning given the core functionality of these components in the forum's operation.
The technical flaw in question exploits the improper handling of user-supplied input within the theme directory configuration parameters. When attackers manipulate the settings[default_theme_dir] parameter, they can inject malicious URLs that the application then attempts to include and execute as PHP code. This vulnerability falls under the category of remote file inclusion attacks, which are classified as CWE-88 in the Common Weakness Enumeration system, representing improper neutralization of argument delimiters in a command. The attack mechanism relies on the application's failure to properly validate and sanitize input parameters before using them in file inclusion operations.
From an operational perspective, this vulnerability presents significant risks to forum administrators and end users. Successful exploitation could enable attackers to upload and execute malicious code, potentially leading to complete system compromise, data theft, or unauthorized access to user information. The impact extends beyond individual forum instances to potentially affect entire networks if multiple forums are hosted on the same server infrastructure. This vulnerability demonstrates the critical importance of input validation and the dangers of allowing user-controllable parameters to influence file system operations, aligning with ATT&CK technique T1190 for exploitation of remote services and T1059 for execution of malicious code through command injection.
Despite the reported vulnerability, it is important to note that both the CVE and multiple third-party security organizations have disputed the validity of this issue due to the presence of protection mechanisms within the affected files. The application's code includes safeguards designed to prevent direct requests to these files, which would typically mitigate the risk of exploitation. This dispute highlights the complexity of vulnerability assessment and the importance of proper context in determining exploitability. The protection mechanisms likely involve checks for legitimate request sources or validation of parameter values, which may prevent the specific attack vectors described in the original vulnerability report. Organizations should consider this disputed status when evaluating their risk assessment and mitigation planning, while still maintaining awareness of the potential attack surfaces and implementing robust input validation practices as defensive measures. The situation underscores the necessity for thorough testing and verification of vulnerability reports, particularly when dealing with complex applications that may include built-in security controls.