CVE-2012-5610 in ownCloud
Summary
by MITRE
Incomplete blacklist vulnerability in lib/filesystem.php in ownCloud before 4.0.9 and 4.5.x before 4.5.2 allows remote authenticated users to execute arbitrary PHP code by uploading a file with a special crafted name.
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Analysis
by VulDB Data Team • 03/31/2025
The vulnerability identified as CVE-2012-5610 represents a critical incomplete blacklist security flaw within the file system handling component of ownCloud software versions prior to 4.0.9 and 4.5.x versions before 4.5.2. This issue resides in the lib/filesystem.php file which governs how the platform processes and validates file uploads. The vulnerability stems from insufficient input validation mechanisms that fail to properly filter malicious file names, creating an avenue for unauthorized code execution.
The technical implementation of this vulnerability exploits the inadequate filtering of file extensions and names during the upload process. Attackers can craft specific file names that bypass the existing security checks, allowing them to upload PHP files with extensions that should be blocked. The incomplete blacklist approach means that the system only blocks a limited set of known dangerous extensions while leaving numerous other potentially harmful file name patterns unfiltered. This design flaw enables authenticated users to upload malicious code that can be executed within the web server context, potentially leading to complete system compromise.
From an operational perspective, this vulnerability poses significant risks to organizations relying on ownCloud for file storage and collaboration. The requirement for authentication means that attackers must first gain valid user credentials, but once obtained, they can leverage this vulnerability to execute arbitrary PHP code on the target system. The impact extends beyond simple code execution to include potential data exfiltration, system infiltration, and lateral movement within the network. According to CWE-20, this vulnerability maps to improper input validation, specifically related to incomplete blacklist implementation, which is classified as a common weakness in software security practices. The attack vector aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where adversaries execute code through PHP file uploads.
The remediation strategy for this vulnerability involves implementing a comprehensive whitelist approach rather than relying on blacklists, ensuring that only explicitly approved file types are accepted for upload. Organizations should immediately upgrade to the patched versions of ownCloud 4.0.9 and 4.5.2, which address the incomplete blacklist implementation. Additional mitigations include implementing strict file name validation, removing PHP execution permissions from upload directories, and deploying web application firewalls to monitor and filter suspicious upload attempts. Security teams should also conduct regular audits of file upload mechanisms and implement proper access controls to limit the impact of potential exploitation. The vulnerability demonstrates the critical importance of proper input validation and the dangers of relying on incomplete security measures that fail to account for all possible attack vectors.