CVE-2009-4090 in telepark.wiki
Summary
by MITRE
Unrestricted file upload vulnerability in ajax/addComment.php in telepark.wiki 2.4.23 and earlier script allows remote attackers to execute arbitrary code by uploading a file with a name containing a NULL byte.
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Analysis
by VulDB Data Team • 08/15/2017
The vulnerability identified as CVE-2009-4090 represents a critical unrestricted file upload flaw within the telepark.wiki content management system version 2.4.23 and earlier. This weakness resides in the ajax/addComment.php script which fails to properly validate file uploads, creating an avenue for remote attackers to bypass security controls and execute malicious code on the target system. The vulnerability specifically exploits the improper handling of file names containing NULL bytes, a technique that can circumvent traditional file validation mechanisms and allow attackers to upload potentially harmful files with executable extensions.
The technical implementation of this flaw stems from inadequate input sanitization within the file upload process. When attackers craft file names containing NULL bytes, they can manipulate the file handling routines to bypass security checks that would normally prevent execution of malicious files. This type of vulnerability falls under CWE-434 which categorizes unrestricted file upload as a serious weakness that can lead to remote code execution, denial of service, or data compromise. The NULL byte injection technique leverages the way certain programming languages and web servers process string termination, allowing attackers to truncate file names and manipulate the upload process to their advantage.
The operational impact of CVE-2009-4090 extends beyond simple code execution, potentially enabling attackers to gain full control over the affected web server. Once an attacker successfully uploads a malicious file, they can execute arbitrary commands on the server, leading to complete system compromise. This vulnerability can result in data theft, service disruption, unauthorized access to sensitive information, and potential lateral movement within the network. The remote nature of the attack means that exploitation does not require local system access, making it particularly dangerous for web applications that are publicly accessible. Organizations running telepark.wiki versions prior to the patched release face significant risk of exploitation, as the vulnerability can be leveraged to establish persistent backdoors or deploy additional malware.
Mitigation strategies for this vulnerability should focus on immediate patching of the telepark.wiki application to version 2.4.24 or later, which contains the necessary fixes for the file upload validation. Additionally, administrators should implement robust file upload validation controls including strict filename sanitization, content type checking, and enforcement of file extension restrictions. The implementation of proper input validation and output encoding techniques aligns with defensive measures recommended in the ATT&CK framework for preventing code injection and remote execution attacks. Organizations should also consider deploying web application firewalls to detect and block suspicious file upload attempts, while implementing network segmentation to limit the potential impact of successful exploitation. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other applications within the organization's infrastructure.