CVE-2015-4606 in Job Fair Extension
Summary
by MITRE
Unrestricted file upload vulnerability in the Job Fair (jobfair) extension before 1.0.1 for TYPO3, when using Apache with mod_mime, allows remote attackers to execute arbitrary code by uploading a file with an executable extension, then accessing it via a direct request to the file in the extension upload folder.
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Analysis
by VulDB Data Team • 04/08/2019
The CVE-2015-4606 vulnerability represents a critical unrestricted file upload flaw within the TYPO3 Job Fair extension version 1.0.0 and earlier. This vulnerability specifically affects installations utilizing Apache web servers with mod_mime module, creating a dangerous attack surface that enables remote code execution. The flaw stems from inadequate input validation and sanitization mechanisms within the extension's file upload functionality, allowing malicious actors to bypass security controls and deploy malicious payloads.
The technical implementation of this vulnerability exploits the interaction between TYPO3's extension handling and Apache's mod_mime module. When users upload files through the jobfair extension, the system fails to properly validate file extensions or content types, particularly when Apache's mod_mime module is present. This creates a scenario where attackers can upload files with executable extensions such as .php, .asp, or .jsp, which then become executable within the web server's document root. The vulnerability specifically targets the extension's upload directory, making it accessible via direct HTTP requests to the uploaded files.
From an operational impact perspective, this vulnerability presents a severe threat to TYPO3 installations using the affected extension. Attackers can leverage this flaw to execute arbitrary code on the target server, potentially leading to complete system compromise, data exfiltration, or establishment of persistent backdoors. The attack requires minimal privileges and can be automated, making it particularly dangerous for web applications that handle sensitive data or serve critical business functions. The vulnerability also aligns with ATT&CK technique T1190 for exploitation of remote services and T1059 for command and script injection.
The root cause of this vulnerability can be traced to CWE-434, which addresses insecure file upload handling, and CWE-20, which covers input validation flaws. The vulnerability demonstrates poor security practices in file handling and access control implementation within the TYPO3 extension framework. The lack of proper file type validation, content inspection, and secure file storage mechanisms creates an exploitable gap that directly enables remote code execution. Additionally, the vulnerability's exploitation path aligns with ATT&CK tactic TA0001 (Initial Access) and TA0002 (Execution) through the use of web-based attack vectors and code execution capabilities.
Security mitigations for this vulnerability primarily involve upgrading to TYPO3 Job Fair extension version 1.0.1 or later, which implements proper file validation and sanitization measures. Organizations should also implement additional defensive controls including restrictive file upload policies, content type validation, and proper access controls for upload directories. Network-level protections such as web application firewalls and upload directory restrictions can provide additional layers of defense. The fix typically involves implementing proper file extension validation, content type checking, and secure file storage practices that prevent executable files from being executed within the web server context.