CVE-2011-1127 in SMF
Summary
by MITRE
SSI.php in Simple Machines Forum (SMF) before 1.1.13, and 2.x before 2.0 RC5, does not properly restrict guest access, which allows remote attackers to have an unspecified impact via unknown vectors.
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Analysis
by VulDB Data Team • 02/09/2019
The vulnerability identified as CVE-2011-1127 affects Simple Machines Forum (SMF) versions prior to 1.1.13 and 2.x versions before 2.0 RC5, specifically within the SSI.php component. This represents a critical access control flaw that undermines the security model of the forum software. The issue stems from insufficient guest access restrictions in the Server Side Includes functionality, creating potential attack vectors that could compromise the integrity and confidentiality of forum data. The vulnerability's impact remains unspecified due to the broad nature of potential attack scenarios that could exploit this weakness.
The technical flaw manifests in the improper handling of guest user permissions within the SSI.php file, which serves as a server-side includes interface for embedding forum content into external pages. This misconfiguration allows unauthorized guest users to bypass normal access controls and potentially execute malicious actions or access restricted resources. The vulnerability operates at the application layer and specifically targets the authentication and authorization mechanisms of the forum software, making it particularly dangerous for public-facing web applications. The flaw aligns with CWE-284, which describes improper access control issues, and represents a classic case of insufficient privilege checking in web applications. Attackers could leverage this weakness to perform unauthorized operations through various vectors including but not limited to data exfiltration, content manipulation, or privilege escalation.
The operational impact of CVE-2011-1127 extends beyond simple unauthorized access, as it could enable attackers to compromise the entire forum infrastructure. Guest users who should normally be restricted from accessing sensitive forum functions could potentially exploit this vulnerability to gain elevated privileges or access confidential information. The unspecified nature of the impact suggests that the vulnerability may allow for multiple attack vectors, including but not limited to cross-site scripting, remote code execution, or data corruption. Organizations running affected SMF versions face significant risk of data breaches, reputational damage, and potential regulatory compliance violations. This vulnerability directly impacts the CIA triad by compromising confidentiality, integrity, and availability of forum resources, and aligns with several ATT&CK techniques including privilege escalation and credential access.
Mitigation strategies for this vulnerability require immediate patching of affected SMF installations to versions 1.1.13 or 2.0 RC5 and later. System administrators should also implement network-level restrictions to limit access to the SSI.php endpoint and monitor for suspicious activity patterns. Additional protective measures include implementing web application firewalls, enforcing strict access controls for guest users, and conducting regular security audits of forum components. The vulnerability demonstrates the critical importance of proper access control implementation and highlights the need for continuous security testing of web applications. Organizations should also consider implementing automated patch management systems to ensure timely remediation of similar vulnerabilities. Security monitoring should focus on identifying unauthorized access attempts and anomalous behavior patterns that might indicate exploitation attempts against the SSI.php component. The incident underscores the necessity of following secure coding practices and adhering to established security frameworks such as those defined by OWASP and NIST for preventing access control vulnerabilities in web applications.