CVE-2015-1375 in Pixabay Images
Summary
by MITRE
pixabay-images.php in the Pixabay Images plugin before 2.4 for WordPress does not properly restrict access to the upload functionality, which allows remote attackers to write to arbitrary files.
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Analysis
by VulDB Data Team • 02/23/2025
The pixabay-images plugin for WordPress suffered from a critical access control vulnerability that existed in versions prior to 2.4. This flaw specifically affected the pixabay-images.php script which handled file upload operations within the plugin's functionality. The vulnerability stemmed from inadequate authentication and authorization checks that allowed unauthenticated users to bypass normal security restrictions. Attackers could exploit this weakness to upload malicious files to arbitrary locations on the target server, effectively compromising the WordPress installation. The vulnerability was classified as a privilege escalation issue that enabled attackers to perform unauthorized operations within the plugin's upload mechanism. This type of flaw represents a significant security risk as it directly undermines the fundamental security model of web applications by allowing unauthorized access to file system operations.
The technical implementation of this vulnerability involved the plugin's failure to properly validate user permissions before executing upload operations. The pixabay-images.php script did not verify whether the requesting user possessed appropriate privileges to perform file uploads or whether the upload request originated from a legitimate administrative session. This lack of proper access control validation created a pathway for remote attackers to submit malicious files through the plugin's interface without requiring valid authentication credentials. The vulnerability was particularly dangerous because it allowed attackers to write files to arbitrary locations rather than being restricted to a specific upload directory. This broad scope of potential file system manipulation enabled attackers to place malicious code in critical system directories or overwrite existing legitimate files. The flaw was categorized as a weakness in authorization controls and could be exploited to achieve persistent access to the compromised system.
The operational impact of this vulnerability was severe and far-reaching for WordPress installations using the affected plugin version. Remote attackers could leverage this weakness to upload web shells, malware, or other malicious payloads that would execute with the privileges of the web server process. This capability enabled attackers to establish persistent backdoors, exfiltrate sensitive data, or use the compromised server for further attacks against other systems. The vulnerability also allowed for arbitrary file creation, which could be used to modify existing WordPress files or create new files that would be executed as part of the web application's normal operation. Organizations running affected versions of the plugin faced potential complete compromise of their WordPress installations, as the vulnerability provided attackers with direct file system access and execution capabilities. The impact extended beyond immediate exploitation to include long-term security degradation of the entire web infrastructure.
Mitigation strategies for this vulnerability required immediate action to upgrade to version 2.4 or later of the Pixabay Images plugin where the access control issues were resolved. System administrators should have implemented comprehensive monitoring of file upload activities and performed regular security audits of WordPress plugins to identify similar vulnerabilities. The fix involved implementing proper authentication checks and authorization validation before allowing any file upload operations to proceed. Security measures should have included restricting file upload directories to specific locations and implementing strict file type validation to prevent execution of malicious code. Organizations should have deployed web application firewalls to detect and block suspicious upload attempts, while also ensuring that WordPress installations followed security best practices such as keeping all plugins and themes updated. This vulnerability highlighted the importance of proper access control implementation and the need for regular security assessments of third-party components in web applications. The incident underscored the critical nature of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect against similar access control weaknesses.