CVE-2011-4902 in TYPO3
Summary
by MITRE
TYPO3 before 4.3.12, 4.4.x before 4.4.9, and 4.5.x before 4.5.4 allows remote attackers to delete arbitrary files on the webserver.
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Analysis
by VulDB Data Team • 11/07/2019
The vulnerability identified as CVE-2011-4902 represents a critical file deletion flaw in the TYPO3 content management system that affected multiple version branches including 4.3.11 and earlier, 4.4.8 and earlier, and 4.5.3 and earlier. This vulnerability stems from inadequate input validation and sanitization mechanisms within the file handling components of the TYPO3 framework, specifically in how the system processes user-supplied file paths and operations. The flaw allows remote attackers to manipulate file system operations through maliciously crafted requests that bypass normal access controls and authorization checks.
The technical implementation of this vulnerability involves the exploitation of insecure direct object references within the TYPO3 file management subsystem. Attackers can leverage this weakness by constructing specially crafted URLs or API calls that reference arbitrary file paths on the web server filesystem. The vulnerability manifests when the application fails to properly validate or sanitize file paths submitted through various interfaces including file upload mechanisms, file management tools, and content editing features. This lack of proper path validation creates a condition where attacker-controlled input directly influences the file system operations without adequate security checks.
The operational impact of CVE-2011-4902 extends beyond simple file deletion to potentially compromise the entire web server infrastructure. Remote attackers can leverage this vulnerability to remove critical system files, web application components, configuration files, or even database backup files that could lead to complete system compromise. The vulnerability enables attackers to execute a wide range of malicious activities including but not limited to removing executable scripts, deleting configuration files that could cause application failures, or targeting log files that could aid in maintaining persistence. This capability aligns with attack patterns documented in the MITRE ATT&CK framework under the T1070.004 technique for "File Deletion" and T1059.007 for "Command and Scripting Interpreter: PowerShell" when combined with other exploitation techniques.
The vulnerability demonstrates characteristics consistent with CWE-22, which describes "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')", and CWE-73, which addresses "External Control of File Name or Path". These weakness classifications highlight the fundamental flaw in how the TYPO3 system handles file path resolution and validation. The vulnerability's exploitation requires minimal privileges and can be executed remotely without authentication, making it particularly dangerous for web applications that process user input. The impact is exacerbated by the fact that the vulnerability affects multiple version lines simultaneously, indicating a systemic design flaw rather than an isolated incident.
Security mitigation strategies for CVE-2011-4902 primarily focus on immediate remediation through version upgrades to the patched releases mentioned in the CVE description. Organizations should implement comprehensive patch management procedures to ensure all TYPO3 installations are updated to versions 4.3.12, 4.4.9, or 4.5.4 and later. Additionally, administrators should consider implementing network-level restrictions to limit access to file management interfaces and implement proper input validation at multiple layers of the application stack. The implementation of web application firewalls and intrusion detection systems can provide additional monitoring capabilities to detect suspicious file operations. Organizations should also conduct thorough security audits of their TYPO3 installations to identify any other potential vulnerabilities that could be exploited in conjunction with this flaw. The vulnerability serves as a reminder of the critical importance of proper input validation and the principle of least privilege in web application security, aligning with defense-in-depth strategies recommended by various cybersecurity frameworks including NIST SP 800-53 and ISO/IEC 27001.